Minimally invasive intact recovery of tissue

ABSTRACT

System, method and apparatus for carrying out the recovery of an intact volume of tissue wherein a delivery cannula distal end is positioned in confronting adjacency with the volume of tissue to be recovered. A capture component formed of a plurality of metal leafs is deployed from the distal end of the delivery cannula. The tips of these leafs carry a pursing cable assembly which is electrically excited to electrosurgically cut around and circumscribe the tissue volume. These pursing cables are tensioned to complete the envelopment of the tissue volumes by drawing the leaf tips together. Drive to the capture component ultimately is developed from an electric motor and electrosurgical cutting current is supplied initially at a boost voltage level and thereafter at a lower normal cutting voltage level.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a Continuation-In-Part of United Statesapplication for patent Ser. No. 09/472,673 entitled: “Minimally InvasiveIntact Recovery of Tissue”, filed Dec. 27, 1999 by Eggers, et al.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] Not applicable.

BACKGROUND OF THE INVENTION

[0003] It is estimated that one out of eight women will face breastcancer at some point during her lifetime, and for women age 40-55,breast cancer is the leading cause of death. While methods for detectingand treating breast cancer initially were crude and unsophisticated,advanced instrumentation and procedures now are available which providemore positive outcomes for patients.

[0004] In the 1800s the only treatment for breast cancer was removal ofthe entire breast. Given that the sole method of detection and diagnosiswas palpation, treatment was only directed when the breast tumor waswell advanced. Modified radical mastectomies are still performed todayfor patients with invasive cancer, such a procedure involving theremoval of the entire breast and some or all of the axillary lymphnodes. Radical or modified radical mastectomies involve serious traumafor the patient during surgery with the severest cosmetic results aftersurgery.

[0005] Another surgical option upon the discovery of malignant tumor iswhat is referred to as breast conserving surgery, which also is referredto as lumpectomy, tumorectomy, segmental mastectomy and local excision.Meant to address the cosmetic concerns associated with removal of thebreast, only the primary tumor and a margin of surrounding normal breasttissue is removed. Determining the proper amount of tissue to be removedinvolves balancing the need to take sufficient tissue to preventrecurrence with the desire to take as little tissue as possible topreserve the best cosmetic appearance. A more limited nodal dissectionnow is performed with the primary purpose being staging rather thantherapy. While an improvement over radical mastectomy, breast-conservingsurgery still involves the removal of large sections of breast tissue.Risks associated with such surgery include wound infection, seromaformation, mild shoulder dysfunction, loss of sensation in thedistribution of the intercostobrachial nerve, and edema of the breastand arm. For more information on invasive tumor therapy, see:

[0006] (1) Harris, Jay R., et al. “Cancer of the Breast.” Cancer:Principles and Practices of Oncology, Fourth Edition. Eds. DeVita, etal. Philadelphia: J.B. Lippincott Co., 1993. 1264-1285.

[0007] (2) Jobe, William E. “Historical Perspectives.” PercutaneousBreast Biopsy. Eds. Parker, et al. New York: Raven Press, 1993. 1-5.

[0008] Mastectomies and breast-conserving surgeries generally areprocedures utilized for invasive tumor. Advances in tumor detection,however, have radically changed the course of diagnosis and treatmentfor a tumor. With the advent of imaging devices, such as the mammogram,suspect tumor may be located when it is of relatively small size. Today,tumor detection generally involves both a mammogram and a physicalexamination, which takes into account a number of risk factors includingfamily history and prior occurrences. Technical improvements inmammogram imaging include better visualization of the breast parenchymawith less exposure to radiation, improvements in film quality andprocessing, improved techniques for imaging, better guidelines for thediagnosis of cancer and greater availability of well-trainedmammographers. With these advancements in imaging technology, a suspecttumor may be detected which is 5 mm or smaller. More recentlysubstantial progress has been witnessed in the technical disciplines ofmagnetic resonance imaging (MRI) and ultrasound imagining. With theseadvances, the location of a lesion is observable as diagnosticlanalyticor therapeutic procedures are carried out.

[0009] In the past, because a tumor normally was not discovered until ithad reached an advanced stage, the issue of whether a tumor wasmalignant or benign did not need to be addressed. With the ability tolocate smaller areas of suspect tumor, this issue becomes of criticalimportance, particularly in light of the fact that only 20% of small,non-invasive tumors are malignant. Tumors identified as being benign maybe left in situ with no excision required, whereas action must be takento excise suspect tissue confirmed to be malignant. In view of the valueof classifying a tumor as malignant or benign, breast biopsy has becomea much-utilized technique with over 1 million biopsies being performedannually in the United States. A biopsy procedure involves the two stepprocess of first locating the tumor then removing part or all of thesuspect tissue for examination to establish precise diagnosis.

[0010] One biopsy option available upon detection of a suspect tumor isan open surgical biopsy or excisional biopsy. Prior to surgery, aradiologist, using mammography, inserts a wire into the breast to locatethe tumor site. Later during surgery, the surgeon makes an incision inthe breast and removes a large section of breast tissue, including thesuspect tissue and a margin of healthy tissue surrounding the tumor. Aswith other similar procedures, such as those described above, opensurgery may result in high levels of blood loss, scarring at thelocation of the incision and permanent disfigurement, due to the removalof relatively large amounts of tissue. Because of the criticalprognostic significance of tumor size, the greatest advantage of theexcisional biopsy is that the entire area of the suspect tumor isremoved. After being removed and measured, the specimen is split by apathologist in a plane that should bisect a tumor if present, then themargin between tumor and healthy tissue is examined. Microscopiclocation of carcinoma near the margin provides information for futureprognosis. Thus the pathology laboratory is oriented to themorphological aspect of analysis, i.e. the forms and structures ofinvolved tissue.

[0011] For information on pathology of breast biopsy tissue, see:

[0012] (3) Rosen, Paul Peter. Rosen's Breast Pathology.

[0013] Philadelphia: Lippincott-Raven Publishers, 1997. 837-858.

[0014] Other less invasive options are available which avoid thedisadvantages associated with open surgery. One such non-invasive optionis that of needle biopsy, which may be either fine needle aspiration orlarge core. Fine needle aspiration (FNA) is an office procedure in whicha fine needle, for example of 21 to 23 gauge, having one of a number oftip configurations, such as the Chiba, Franzeen or Turner, is insertedinto the breast and guided to the tumor site by mammography orstereotactic imaging. A vacuum is created and the needle moved up anddown along the tumor to assure that it collects targeted cellularmaterial. Generally, three or more passes will be made to assure thecollection of a sufficient sample. Then, the needle and the tissuesample are withdrawn from the breast.

[0015] The resulting specimen is subject to a cytologic assay, asopposed to the above-noted morphological approach. In this regard, cellstructure and related aspects are studied. The resultant analysis hasbeen used to improve or customize the selection of chemotherapeuticagents with respect to a particular patient.

[0016] While a fine needle aspiration biopsy has the advantages of beinga relatively simple and inexpensive office procedure, there are somedrawbacks associated with its use. With fine needle aspiration, there isa risk of false-negative results, which most often occurs in casesinvolving extremely fibrotic tumor. In addition, after the procedure hasbeen performed there may be insufficient specimen material fordiagnosis. Finally, with fine needle aspiration alone the entire area ofsuspect tissue is not removed. Rather, fragmented portions of tissue arewithdrawn which do not allow for the same type of pathologicalinvestigation as the tissue removed during an open surgery biopsy.

[0017] This limitation also is observed with respect to large coreneedle biopsies. For a large core needle biopsy, a 14 to 18 gauge needleis inserted in the breast having an inner trocar with a sample notch atthe distal end and an outer cutting cannula. Similar to a fine needleaspiration, tissue is drawn through the needle by vacuum suction. Theseneedles have been combined with biopsy guns to provide automatedinsertion that makes the procedure shorter and partially eliminateslocation mistakes caused by human error. Once inserted, multiplecontiguous tissue samples may be taken at a time.

[0018] Samples taken during large core needle biopsies may be anywherefrom friable and fragmented to large pieces 20 to 30 mm long. Thesesamples may provide some histological data, unlike fine needleaspiration samples, however, they still do not provide the pathologicalinformation available with an open surgical biopsy specimen. Further, aswith any mechanical cutting device, excessive bleeding may result duringand following the procedure. Needle biopsy procedures are discussed in:

[0019] (4) Parker, Steve H. “Needle Selection” and “StereotacticLarge-Core Breast Biopsy.” Percutaneous Breast Biopsy. Eds. Parker, etal. New York: Raven Press, 1993. 7-14 and 61-79.

[0020] A device which is somewhere between a needle biopsy and opensurgery is referred to as the Advanced Breast Biopsy Instrumentation(ABBI). With the ABBI procedure, the practitioner, guided bystereotactic imaging, removes a core tissue sample of 5 mm to 20 mm indiameter. While the ABBI has the advantage of providing a large tissuesample, similar to that obtained from an open surgical biopsy, thecylindrical tissue sample is taken from the subcutaneous tissue to anarea beyond the suspect tumor. For tumors embedded more deeply withinthe breast, the amount of tissue removed is considerable. In addition,while less expensive than open surgical biopsy, the ABBI has provenexpensive compared to other biopsy techniques, and it has been notedthat the patient selection for the ABBI is limited by the size andlocation of the tumor, as well as by the presence of very denseparenchyma around the tumor. For discussion on the ABBI, see:

[0021] (5) Parker, Steve H. “The Advanced Breast Biopsy Instrumentation:Another Trojan Hourse?” Am. J.

[0022] Radiology 1998; 171: 51-53.

[0023] (6) D'Angelo, Philip C., et al. “Stereotactic Excisional BreastBiopsies Utilizing the Advanced Breast Biopsy Instrumentation System.”Am J Surg. 1997; 174: 297-302.

[0024] (7) Ferzli, George S., et al. “Advanced Breast BiopsyInstrumentation: A Critique.” J Am Coll Surg 1997;

[0025]185: 145-151.

[0026] Another biopsy device has been referred to as the Mammotome andthe Minimally Invasive Breast Biopsy (MIBB). These devices carry out avacuum-assisted core biopsy wherein fragments of suspect tissue areremoved with a 11 to 14 gauge needle. While being less invasive, theMammotome and MIBB yields only a fragmentary specimen for pathologicalstudy. These devices therefore are consistent with other breast biopsydevices in that the degree of invasiveness of the procedure necessarilyis counterbalanced against the need for obtaining a tissue sample whosesize and margins are commensurate with pathology requirements fordiagnosis and treatment.

[0027] In a co-pending application for United States patent entitled“Minimally Invasive Intact Recovery of Tissue”, Ser. No. 091472,673,filed Dec. 27, 1999 by Eggers, et aL, an instrument for removing atargeted tissue volume in a minimally invasive manner is described. Thatinstrument includes a tubular delivery cannula of minimum outerdiameter, the tip of which is positioned in confronting adjacency with atissue volume to be removed. Following such positioning, theelectrosurgically excited leading edge of a capture component isextended forwardly from the instrument tip to enlarge whileelectrosurgically cutting and surrounding or encapsulating a tissuevolume, severing it from adjacent healthy tissue. Following suchcapture, the instrument and encaptured tissue volume are removed throughan incision of electively limited extent.

BRIEF SUMMARY OF THE INVENTION

[0028] The present invention is addressed to apparatus, system andmethod for retrieving a tissue volume in intact form utilizing surgicalinstrumentation which is minimally invasive. This instrumentationincludes a tubular delivery cannula of minimum outer diameter, the tipor distal end of which is positioned in confronting adjacency with thetarget tumor or tissue volume to be removed. Such positioning isfacilitated through the utilization of a forwardly disposed precursorelectrosurgical electrode assembly. Located within the interior channelof this delivery cannula is a capture component configured with aplurality of relatively elongate leafs mutually interconnected at theirbase to define a polygonal cross-sectional configuration. Each of theleafs terminates forwardly with a transversely bent, eyelet containingtip. Slidably extending through each eyelet is an electricallyconductive pursing cable of a pursing cable assembly which is thenattached to another leaf tip and extends rearwardly through a small,flexible guide tube attached to the leaf for connection with the cableterminator component of a drive assembly. The drive assembly is drivenforwardly by a motor, translation assembly and abuttably engagedtransfer assembly to actuate the capture component. This actuation iscarried out by electrosurgically exciting the pursing cable assembly toestablish a cutting leading edge. Then, the leafs, carrying the excitedcable assembly, are driven at an attack angle mutually outwardly througha guidance assembly to an extent that the cutting leading edge reachesan effective maximum diameter extending about the tissue volume. At thisjuncture, the cable terminator encounters a stop member and the leaftips are drawn mutually inwardly to define a curvilinear profile toclose the leading edge about the tissue volume as their forward movementcontinues. These pursing cables, now under stress and constrained withinthe guide tubes at the outer surfaces of the leafs, contribute to thestructural stability of the resultant tissue specimen containmentstructure. Adjustment of the number of leafs associated with a givencable establishes the rates of containment closure as well as the degreeor extent of curvature of the noted curvilinear profile. Followingcapture, the instrument is removed from adjacent tissue with theretained tissue specimen.

[0029] By employing this noted cable terminator and stop memberconstruction, the diameter of the delivery cannula can be maintained ata constant minimum value, while the instrument enjoys the capability ofproviding an important range of capture component leading edge maximumeffective diameters. The relatively straightforward structuring of thedelivery cannula, capture component and drive assembly permits theirfabrication as a discrete disposable component, removably insertablewithin a hand maneuvered housing.

[0030] Practitioner control over the instrument principally is providedfrom either three button-type switches mounted upon its housing assemblyor from a three pedal footswitch. A remotely located electrosurgicalgenerator and control assembly is coupled by cable with the housingassembly and footswitch. In carrying out the retrieval procedure,following preliminary self checks for proper electrode and instrumentconnections and transfer assembly positioning, either a position switchon the housing or the footswitch is actuated by the practitioner. Thisenergizes a forwardly disposed precursor electrode from theelectrosurgical generator, initially at a boost voltage level for ashort boost interval, then at a lower, normal cutting voltage level asthe forward region of the delivery cannula is positioned in confrontingadjacency with the involved tissue volume. The switch utilized then isreleased to terminate this positioning mode of the procedure.

[0031] The delivery cannula being thus positioned, the practitionermomentarily depresses an arm capture switch button on the housingassembly to cause the control assembly to enter an arm capture modewhich disables the housing mounted position switch. Next, thepractitioner depresses either the capture switch or capture footswitchwhich now performs a capture function. Upon depressing and continuing todepress a capture switch mounted upon the housing assembly or thecapture footswitch, the control assembly enters a capture mode. At thecommencement of this capture mode, motor performance initially istested, whereupon the motor is de-energized as electrosurgical currentat the boost voltage level is applied to the capture component cablesfor a short boost interval. Following this boost interval, current at alower, normal cutting voltage level is asserted from the electrosurgicalgenerator in conjunction with activation of the motor drive and theleafs commence to be deployed from the guidance assembly. During theensuing actuation of the capture component under motor drive, the loadcharacteristics of the motor are monitored for both motor performanceand for detecting the completion of capture. In the latter regard, aforward stall condition is detected to determine capture completioncommencing a capture complete mode. In this capture complete mode, motorrotational direction is reversed to cause a return of the transferassembly to its original or home position, thus releasing the driveassembly of the disposable component from engagement. The deliverycannula with captured tissue specimen is removed from the incision andthe disposable component of the instrument is removed from the housingassembly. When so removed, the practitioner may manually retract thedrive component to a position causing the capture component leafs andassociated pursing cable assembly to assume an open cup formationpermitting facile access to the recovered specimen.

[0032] If, during the capture mode, the practitioner wishes to halt theprocedure, the capture switch or capture footswitch is released to causethe control assembly to enter a pause mode. In this pause mode the motoris de-energized and electrosurgical cutting current to the capturecomponent cable assembly is terminated. Return to capture modeperformance is carried out by the practitioner by again depressing thehandle mounted capture switch or capture footswitch.

[0033] The remotely disposed electrosurgical generator is configuredwith an input treatment network which responds to a conventional powerinput to derive an interim direct current (d. c.) voltage output ofrelatively higher value, for example, 380 volts. This input treatmentpreferably includes both EMI filtering as well as power factorcorrection. In general, a boost converter network is employed inconjunction with this power factor correction. The interim d. c. voltagethen is applied to a 100 kilohertz inverter which provides a rectangularwaveform output, the peak-to-peak voltage amplitude of which isdeveloped by an inverter control network which performs in a resonanttransition phase shift mode to achieve soft switching and quite accuratecontrol of the noted voltage amplitude. This amplitude controlled outputthen is directed through an isolation transformer to rectification andfiltering to evolve a d.c. link voltage, the amplitude of which is usedas a control for the voltage amplitude of the ultimately derivedelectrosurgical boost and normal cutting voltage levels. In this regard,the d. c. link voltage input is directed to the input of a resonant tankcircuit for deriving a sinusoidal output at a stable electrosurgicalfrequency which is directed to the primary side of a high voltagetransformer. From the secondary side of that high voltage transformer,an output stage directs electrosurgical energy to the precursorelectrodes and, alternately, to the capture component cable assembly. Toprovide control over the assertion of electrosurgical energy, the systememploys a relay disconnect function within the d. c. link voltagecircuit path.

[0034] The housing assembly also incorporates a manually graspablestabilizer grip which is removably connectable at either side of theinstrument to accommodate both right handed and left handedpractitioners. Further, the grip is adjustable longitudinally toaccommodate for the size of the hand of the practitioner to facilitatereaching the three button switches mounted upon the housing assembly.

[0035] Other objects of the invention, will in part, be obvious andwill, in part, appear hereinafter. The invention, accordingly, comprisesthe method, system and apparatus possessing the construction,combination of elements, arrangement of parts and steps which areexemplified in the following detailed description. For a fullerunderstanding of the nature and objects of the invention, referenceshould be made to the following detailed description taken in connectionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1 is a perspective view of the system of the inventionshowing a hand held instrument, control console, return electrode,footswitches and a vacuum system component;

[0037]FIG. 2 is a perspective view of the instrument shown in FIG. 1with a disposable component being shown removed from a reusable housing;

[0038]FIG. 3 is an exploded view of the reusable housing shown in FIG.2;

[0039]FIG. 4 is a partial sectional view of the instrument shown in FIG.1 with portions broken away;

[0040]FIG. 5 is a sectional view taken through the plane 5-5 shown inFIG. 4;

[0041]FIG. 6 is a sectional view taken through the plane 6-6 shown inFIG. 5;

[0042]FIG. 7 is a bottom view of the instrument shown in FIG. 1;

[0043]FIG. 8 is a front view of the reusable housing shown in FIG. 2;

[0044]FIG. 9 is a bottom view of the instrument shown in FIG. 1 adjustedfor utilization by a practitioner with a larger right hand;

[0045]FIG. 10 is a bottom view of the instrument of FIG. 9 shownadjusted for accommodating a small left hand of a practitioner;

[0046]FIG. 11 is a bottom view of the instrument of FIG. 1 showing apistol grip form of support;

[0047]FIG. 12 is side view of the disposable component of the instrumentas shown in FIG. 2;

[0048]FIG. 13 is a bottom view of the disposable component of FIG. 12;

[0049]FIG. 14 is a sectional view taken through the plane 14-14 shown inFIG. 13;

[0050]FIG. 15 is an enlarged partial sectional view taken at therearward portion of the disposable component shown in FIG. 14;

[0051]FIG. 16 is a sectional view taken through the plane 16-16 shown inFIG. 12;

[0052]FIG. 17 is a sectional view taken through the plane 17-17 shown inFIG. 12;

[0053]FIG. 18 is a sectional view taken through the plane 18-18 shown inFIG. 13;

[0054]FIG. 19 is a sectional view taken through the plane 19-19 shown inFIG. 18;

[0055]FIG. 20 is a sectional view taken through the plane 20-20 shown inFIG. 18;

[0056]FIG. 21 is a top view of a leaf assembly employed with thedisposable component shown in FIG. 2;

[0057]FIG. 22 is a general sectional view of a capture component leafassembly and drive rod;

[0058]FIG. 23 is a partial plan view of a leaf employed with thestructure shown in FIG. 21 as it appears prior to the bending of its tipportion;

[0059]FIG. 24 is a sectional view taken through the plane 24-24 shown inFIG. 23;

[0060]FIG. 25 is a partial view of the leaf shown in FIG. 23 with itstip bent into an operative orientation;

[0061]FIG. 26 is a front view of the forward portion of the instrumentshown in FIG. 1 with components oriented prior to deployment of capturecomponent leafs;

[0062]FIG. 27 is a front view of the forward portion of the instrumentof FIG. 1 showing the orientation of components as the leafs of itscapture component are being deployed;

[0063]FIG. 28 is a partial sectional view of the disposable component ofthe instrument shown in FIG. 1 schematically showing a deployment ofcapture component leafs to a maximum diametric extent;

[0064]FIG. 29 is a partial sectional view of the instrument of FIG. 28schematically showing the orientation of the capture component leafs atthe completion of capture of a tissue volume;

[0065]FIG. 30 is a partial sectional view of the instrument of FIG. 29schematically showing an orientation wherein capture component leafshave been retracted manually for tissue sample access;

[0066]FIG. 31 is a partial sectional view of the instrument shown inFIG. 1 with the capture component leafs schematically depicted at amaximum diametric extent orientation for use with a larger tissue volumesample;

[0067]FIG. 32 is a partial sectional view of the instrument of FIG. 31schematically showing the orientation of capture component leafs in anorientation of full capture;

[0068]FIG. 33 is a plan view of the rear cover of the console shown inFIG. 1;

[0069]FIG. 34 is a block schematic diagram of the electrosurgicalgeneration and control features of the system of the invention;

[0070]FIG. 35 is an insulation diagram for the control system shown inFIG. 34;

[0071]FIGS. 36A and 36B combine as labeled thereon to describe theinterconnections of the printed circuit boards mounted with the consoleshown in FIG. 1 and associated peripheral components;

[0072]FIGS. 37A and 37B combine as labeled thereon to provide aschematic circuit diagram showing the EMI filter, front panel switch,and PFC boost converter components shown in block form in FIG. 34;

[0073]FIG. 38 is an electrical schematic diagram showing a relaysolenoid component employed with contacts shown in FIG. 37A;

[0074]FIG. 39 is an electrical schematic diagram of a temperatureresponsive component employed with the console shown in FIG. 1;

[0075]FIG. 40 is an electrical schematic diagram of a power supplydedicated to provide input power to a motor contained in the reusablehousing of the instrument as shown in FIG. 4;

[0076]FIG. 41 is an electrical schematic diagram of one low voltagepower supply shown in block diagrammatic form in FIG. 34;

[0077]FIG. 42 is an electrical schematic diagram of a motor drive shownin block schematic form in FIG. 34 and further showing the solenoidcomponents of relays employed with the system of the invention;

[0078]FIGS. 43A and 43B combine as labeled thereon to provide anelectrical circuit diagram of a 100 KHz inverter, an isolationtransformer, a rectifier, an LC filter; relay disconnects, an RFinverter, a high voltage transformer and a high voltage output stageshown in block diagrammatic fashion in FIG. 34;

[0079]FIG. 43C is a schematic pulse diagram illustrating the operationof the resonant transition phase shift converter shown in 43A;

[0080]FIGS. 44A and 44B combine as labeled thereon to provide anelectrical schematic diagram of a link voltage evaluation circuit and acontroller for a power factor correction boost converter with associatedenablement circuitry;

[0081]FIG. 45 is an electrical schematic diagram of a primary side powersupply;

[0082]FIG. 46 is an electrical schematic diagram of a control circuitfor providing phase shift resonant transition control;

[0083]FIG. 47A is an electrical schematic diagram of a control circuitfor adjusting d.c. link voltage;

[0084]FIG. 47B is an electrical schematic diagram of a reference voltagederiving circuit;

[0085]FIG. 47C is an electrical schematic diagram of a multipliercircuit for deriving an output power monitoring signal;

[0086]FIG. 48 is an electrical schematic diagram of a control circuitutilized with an FF inverter;

[0087]FIG. 49 is an electrical schematic diagram of a circuit foramplifying motor current;

[0088]FIG. 50 is an electrical circuit schematic diagram of a motorcurrent monitoring circuit;

[0089]FIG. 51 is an electrical schematic diagram of a motor monitoringelectrical circuit;

[0090]FIG. 52 is an electrical schematic diagram of a motor monitoringelectrical circuit;

[0091]FIG. 53 is an electrical schematic diagram of a motor monitoringelectrical circuit;

[0092]FIG. 54 is an electrical schematic diagram showing a derivation ofreset and enable signals;

[0093]FIG. 55 is an electrical schematic diagram of a circuit derivingan over-current condition;

[0094]FIG. 56 is an electrical schematic diagram of a circuit formonitoring an over-voltage condition;

[0095]FIG. 57 is an electrical schematic diagram of a circuit formonitoring power level;

[0096]FIG. 58 is an electrical schematic diagram of a circuit monitoringfor over-temperature conditions;

[0097]FIG. 59 is an electrical schematic diagram of a circuit formonitoring the level of d.c. link voltage;

[0098]FIG. 60 is an electrical schematic diagram showing a circuitderiving footswitch and vacuum switch actuation inputs;

[0099] FIGS. 61A-61E combine as labeled thereon to describe aprogrammable logic device based circuit with associated output bufferingand filtering;

[0100]FIG. 62 is an electrical schematic diagram of a power supply;

[0101]FIG. 63 is an electrical schematic diagram of a circuit formonitoring a low voltage power supply;

[0102]FIG. 64 is an electrical circuit diagram illustrating thetreatment of programmable logic device (PLD) signal inputs and outputs;

[0103]FIG. 65 is an electrical circuit diagram of an audio control;

[0104] FIGS. 66A-66C combine as labeled thereon to describe frequencygeneration and test switching components of a patient circuit safetymonitor (PCSM) circuit;

[0105]FIG. 67 is an electrical schematic diagram of a power supply;

[0106]FIGS. 68A and 68B combine as labeled thereon to illustrate acircuit for carrying out a window based analysis of a return electrodetest;

[0107]FIG. 69 is a schematically portrayed timing chart relating timewith cutting voltages and motor operation;

[0108]FIG. 70A is a schematic representation of a patient and anelectrosurgical system provided to demonstrate tissue impedance andtotal impedance;

[0109]FIG. 70B is a schematic representation of a portion of theillustration of FIG. 70A;

[0110]FIG. 71 is a schematic chart demonstrating the formation of an arcwith a conventional electrosurgical active electrode of fixed geometry;

[0111]FIG. 72 is a graph relating time with applied voltage and totalresistance for an electrosurgical system according to the invention;

[0112]FIG. 73 is a graph showing an application of boost voltage andresultant current; and

[0113] FIGS. 74A-74G combine as labeled thereon to provide a flow chartdescribing the methodology of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0114] A predominate characteristic of the invention resides in theemployment of a capture component in conjunction with a deliverycannula, This capture component is configured with a forward portionwhich extends to a forwardly disposed cutting leading edge which iselectrosurgically excited to provide for electrosurgical cutting.Targeted tumor or tissue along with adjacent healthy tissue iscircumscribed or encapsulated by this capture component through theutilization of a pursing cable assembly which both provides the notedelectrosurgical cutting and constricts the leading edge to, in effect,encapsulate the incised tissue volume. The capture component isimplemented with five elongate flexible metal leafs the tips of whichare formed with eyelets for receiving cables of the noted pursing cableassembly. By selecting a component orientation establishing where apursing or constricting action commences, the maximum leading edgeperiphery for capture may be elected and, typically, may range, forexample, from about a 10 mm to about a 40 mm effective diametric extent.Initial positioning of the delivery cannula tip in confronting adjacencywith a tissue volume is facilitated through the utilization of aprecursor electrosurgical electrode assembly located at the tip.Following appropriate positioning of the tip, a motorized drive isenabled to actuate the capture component thus providing an optimizedrate of movement of the leading edge positioned electrosurgical cuttingcables about the target tissue. A desirable feature of the system of theinvention resides in the incorporation of the delivery cannula and cableimplemented capture component with a disposable support housing. Thatdisposable component is mounted with reusable motorized drive andcontrol components. The term “cannula” as used herein is intended torefer to any elongate surgical delivery structure, rigid or flexible,having a capability for deploying electrosurgical components.

[0115] Referring to FIG. 1, a system according to the invention isrepresented in general at 10. System 10 includes a tissue retrievalinstrument or apparatus represented generally at 12 which includes apolymeric housing assembly represented generally at 14. Housing assembly14 comprises a re-useable housing 15 and a disposable support housing(seen at 108 in FIG. 2). Housing 15 is formed of two identically moldedcomponents shown as housing right side 16 and a housing left side 18.Sides 16 and 18 extend mutually outwardly from a medial planerepresented at a joint line 20. An elongate delivery cannula representedat 22 is shown supported from the forward portion of the housingassembly 14 which extends along a longitudinal axis 58. A distal end ofthe delivery cannula extends through a rotatable threaded connector 24as well as a freely rotatable suction manifold 26 which is retained inposition by a collar 28. The forward region of the cannula 22, asrepresented at 30 extends to a distal end or tip 32. A flexible suctionconduit providing a body fluid, smoke and steam evacuation function isshown at 34 extending from the manifold 26 beneath a grip connector 36through a guide 38 and connector 40 to the input 42 of the housing orconsole of a vacuum system 44. System 44 may be activated by a consolemounted switch 46 or from a foot pedal switch represented at 48 havingan electrical cable connection with the system 44 as represented at 50.Smoke, steam evacuation from the distal end 32 is called for to avoidthermal injury to tissue due to a migration of steam back along theexterior surface of delivery cannula 22. A plug 41 is provided to closeconnector 40 and control any fluid movement within conduit 34 at thetermination of a procedure.

[0116] Grip connectors are positioned on both the right and left housingsides 16 and 18, that at side 16 being revealed at 36. These connectorsare utilized to support a hand engaged stabilizer grip, for example, theannulus-shaped grip represented at 52 which is shown coupled to the lefthousing side 18 for use by a right handed practitioner. Positioned atthe forward portion of housing assembly 14 and accessible from thestabilizer grip 52 are three button switches 54-56 which will be seen tofunction respectively as an arm/disarm switch; an energize positionswitch; and a start tissue capture switch. Immediately above theswitches 54-56 on both the right hand housing side 16 and left handhousing side 18 are linear arrays of indicator lights one such arraybeing represented generally at 60 in connection with right housing side16. The arrays as at 60 are implemented with light emitting diodes(LEDs) and provide visual cues which, from front to rear provide astart/reset cue as a green light; a tissue capture complete cue providedas a green light; a start tissue capture cue (above switch 56) providedas a yellow light; an energize/position cue (above switch 55) providedas a yellow light; and an arm/disarm tissue capture cue (above switch54) provided as a green light. Energization and control is provided tothe instrument 12 via a multi-strand cable 62 which connects with acontrol assembly and electrosurgical generator console or controllerrepresented generally at 64. Connection is shown through a multi-leadconnector 66 which is coupled to a housing connector 67.

[0117] The electrosurgical components of the apparatus 12 perform inmonopolar fashion. Alternatively, a return electrode could be positionedon the surface of cannula 22 near its distal end in place of theillustrated use of a return electrode pad attached to skin of patient.For the former arrangement, a conventional large, dispersive returnelectrode assembly as at 68 is positioned adjacent the skin surface ofthe patient. Assembly 68 is configured having two electrode components70 and 72 which are connected via cable 74 and connector 76 to a console64 connector 77. At the time of attachment with an initially powered(switch 82) console 64, a patient circuit safety monitor circuit (PCSM)carries out a self test. Upon subsequent start/reset actuation (switch92) a fault test with respect to the two electrode components 70 and 72of the assembly 68 is performed. In the event the latter test fails,then both visual and aural pulsation warning cues are activated and theprocedure is halted. The visual cue is implemented with a red LED 78located above the connector 76. Proper connection of the cable 62 andconnector 66 with the console 64 connector 67 is indicated by anilluminated green LED 80 positioned above connector 67. This connectiontest is carried out by directing current to a coding resistor withinhousing assembly 14. To the right of connector 67 is an on/off powerinput switch 82. When switch 82 is in an on orientation, a green LED 84is energized. A second three-pedal footswitch 86 is coupled via a cable88 to the rear panel of the console 64. Pedal 86 a of this footswitchfunctions during an initial portion of the procedure utilizinginstrument 12 to alternately activate a precursor electrosurgicalcutting electrode assembly located at the distal end 32 of deliverycannula 22. Footswitch 86 also performs with respective pedals 86 b and86 c to alternatively enter the arm/disarm mode and to activate thecapture electrode during a capture procedure, the practitioner beingrequired to depress either footswitch 86 c or fingerswitch 55 throughoutthat procedure in order to enable the capture activity to proceed.Release of either footswitch 86 c or fingerswitch 56 during the captureprocedure will cause the system to enter a pause mode. It may beobserved that the energize/position, arm/disarm and start tissue captureswitch functions of respective switches 55, 54 and 56 are emulated atthree-pedal switch 86 as shown respectively at 86 a-86 c.

[0118] Visual cuing corresponding with that at housing assembly 14 alsois provided at the console 64. In this regard, a start/reset switch 92is operationally associated with an LED 94 which illuminates in a greencolor upon actuation of that switch. A yellow position mode visual cuerepresenting an energization of the noted precursor electrode is shownat 96. This LED provides a yellow output during the electrosurgicaladvancement of the delivery cannula tip 32 into confronting adjacencywith a targeted tissue volume. Next, a green arm capture mode visual cueis provided by an LED 98 to represent an arming of the tissue capturefeature of instrument 12. Once the arm/disarm button is depressed, theenergize/position fingerswitch 55 or footswitch 86 a is no longeractivatable. However, the practitioner may return to the position modeby again depressing arm/disarm fingerswith 54 or footswitch 86 bfollowed by an actuation of fingerswitch 55 or footswitch 86 a. A yellowcapture mode visual cue is provided by an LED 100 to represent the startof and carrying out of a tissue capture procedure and upon completion ofsuch capture, a green capture complete mode visual cue is provided by agreen LED 102. Finally, the pause mode condition is represented by agreen LED, provided at 104. Aural cues are provided by a speaker locatedat the rear of console 6A. in general, a continuous tone is providedwherever electrosurgical cutting is taking place. A pulsed tone occursin the event of a return electrode 68 fault. Because of the above-notedopportunity for steam migration, it is preferred that system 10 providean assurance that the vacuum system as represented at housing or console44 be actuated. Preferably, the control assembly of console 64 functionsto permit commencement of the procedure only upon a turning on of system44. Such a monitoring of system 44 is accomplished with a vacuumactuated switch shown at block 51 attached within conduit 34. Themonitoring output to console 64 is represented at arrow 53.

[0119] Referring to FIG. 2, the disposable component indicated generallyat 108, of the instrument 12 is revealed in an orientation prior toinsertion within the reusable, motor containing housing 15. In thefigure, delivery cannula 22 is seen extending forwardly from acylindrically shaped disposable support housing 110. The forward regionof support housing 110 supports the rotatable connector 24. In thisregard, it may be observed that the connector 24 is configured withexternal threads 112 which are fixed for rotation with a knurled flange114. At the rearward end of support housing 110 there is located anupstanding indexing pin 116 which, during installation of the disposableassembly, is slidably received within an upwardly disposed slot 118extending internally along an elongate receiving cavity 166 withinhousing 15.

[0120] Positioned opposite indexing pin 116 on support housing 110 aretwo spaced apart electrical contacts 120 and 122 which are oriented tomake wiping contact with corresponding electrical terminals disposedwithin housing 15 upon insertion of support housing 110 within thereceiving cavity 166. Contacts 120 and 122 selectively receiveelectrosurgical cutting current applied respectively to the precursorelectrode at tip 32 and the pursing cables associated with the capturecomponent. Those cables extend from the capture component to a cableterminator component having guidance tabs or ears one of which isrevealed at 124 slidably mounted within an elongate stabilizer slot 126arranged in parallel with axis 58. A corresponding guidance tab and slotcombination is found in the opposite side of the support housing 110.Located forwardly of the slots as at 126 are two additional elongatedrive slots one of which is shown at 130 similarly arranged in parallelwith axis 58. The outwardly extending ears or guide tabs of a driveassembly drive member extend from these slots and are seen at 134 and136. These ears or tabs 134 and 136 support rearwardly disposed drivensurfaces which are used to impart forward movement to the drive assemblyfunctioning, in turn, to deploy the capture component from deliverycannula 22. When the support housing 110 is installed within thereceiving cavity or region 166 of housing 15 shown generally at 166,these ears or tabs 134 and 136 pass through oppositely disposed notchesshown respectively at 138 and 140 provided at the forward portion ofhousing 15. Similarly, a notch 142 is located forwardly within reusuablehousing 15 to permit passage of the electrical terminals 120 and 122.Note, that the forward portion of reusuable housing 15 also is providedwith internally disposed threads 144 at the entrance of its receivingcavity or region 166. The axis of that receiving region is coincidentwith instrument axis 58. The figure also reveals that the axis ofcannula 22 is coincident with instrument axis 58. Accordingly, when thesupport housing 110 is inserted within the receiving cavity of housing15, the knurled flange 114 of connector 24 is rotated to providethreaded engagement between threaded surface 112 and internal threads144.

[0121] Referring to FIG. 3, the assembly of the reusable components ofthe apparatus 12 is revealed in exploded fashion. In the figure, theexterior surface of the right side 16 of housing 15 is revealed and thecorresponding interior of left housing left side 18 is revealed. Thesetwo sides are symmetrical and identical. Side 16 is shown as beingformed with a rectangular opening 145 into which the pier portion 146 ofconnector 36 is attached. Fixed to the upper side of this pier 146 is anelongate platform 148 in which indentations are formed for positioningengagement with a threaded component 158 of the stabilizer grip as at52. The underside of that grip 52 appears in the figure. That undersideis formed with an inverted, T-shaped slot 150 which is configured toride over the platform 148. In this regard, a connector 152 which isattached to the right housing side 18 is revealed in adjacencytherewith. This connector also is formed with an elongate platform 154which is fixed to a pier 156, in turn fixed to side 18 oppositeconnector 36. As apparent from the figure, the stabilizer grip 52 may beslid forwardly or rearwardly to accommodate the hand size of the user.Each of the housing sides 16 and 18 is formed with one half of a motormount chamber as shown, for example, at 160 in connection with housingside 18. Positioned just forwardly of the chamber 160 are bulkheadsdefining a seal chamber 162. A forward region of each housing side isconfigured with one half of a thrust bearing chamber as represented at164 in connection with housing side 18.

[0122] Positioned within the motor mount chamber as at 160 is a motorand planetary gear train assembly represented generally at 170 whichincorporates a motor component 170 a in combination with a planetarygear assembly 170 b. Assembly 170 is relatively loosely positionedwithin chamber 160 to the extent that it has a freedom of movement withthe exception of rotational movement. In this regard, a torque stopcomponent 172 prohibiting overall motor assembly rotation is coupled tothe forward or output end of the assembly 170. That output is connectedthrough a stainless steel flexible bellows-shaped coupler 174 extendingthrough a flexible fluid seal to connection with a translation component176 implemented with the threaded elongate rod of a ball screw mechanismarranged in parallel with the longitudinal axis 58 of the apparatus 12.This bellows 174 provides a torsionally rigid, but axially flexiblecoupling reducing the vagaries of elongate mechanical-rotational forcetransmission. Bellows couplers as at 174 are marketed under a modeldesignation SC-3 by Servometer Corp. of Cedar Grove N.J. Alternatively,other flexible coupling components may be used for this purposeincluding u-joint coupling, couplings with elastomeric members,three-piece “spider” couplings, disc couplings and helical beamcouplings (e.g., See “Flexible Shaft Couplings”, MacMaster-Carr SupplyCompany, Cleveland, Ohio).

[0123] Rotatably driven from the motor assembly 170 through the bellowscoupler 174, the translation component is attached to a thrust bearing178. Bearing 178, in turn, is mounted and secured within the thrustbearing chamber 164. With this arrangement, a freedom of movement isprovided for the entire assembly rearwardly of the thrust bearing 178including motor assembly 170, coupling 174 and translation component 176permitting the motor assembly 170 to be mounted in self aligningconfinement within the housing 14. Thus, binding or like phenomena areavoided in connection with the motor drive actuator system. Thetranslation component 176 is threadably engaged with a transfer assemblyrepresented generally at 180 which comprises a ball screw or nutcomponent 182 and a generally Y-shaped yoke 184 which is configured toextend to a position spaced from but aligned for driven engagement withthe tabs or ears 134 and 136 (FIG. 2) when the support housing 110initially is inserted in the receiving cavity 166. Mounted upon an upperwall portion of the motor mount chamber 160 are two electrical contacts186 and 188 which are retained in place by a polymeric contact clamp 190and which function to supply electrosurgical cutting current to the twocontact surfaces 120 and 122 (FIG. 2) located on the disposable supporthousing 110. Motor assembly 170 is protected from the high voltageconditions extant at the terminals 186 and 188 by a motor cover 192.FIG. 3 also reveals a polymeric forwardly disposed header 194 which isinternally threaded as at 144 to provide threaded connection with theconnector 24 located upon the noted disposable housing 110.

[0124] Openings are provided in each of the housing sides 16 and 18 toreceive flexible polymeric switch buttons. These notch-like openings arerevealed at 196-198 in connection with side 16 and at 199-201 inconnection with housing side 118. Extending through the notch-likeopenings 196-201 are flexible molded switch buttons formed with assembly204. These switch buttons as at 54-56 cooperate with switch componentsshown respectively at 206-208 formed within one side of a printedcircuit board 210. The opposite side of circuit board 210 supports fivelight emitting diodes (not shown) which, in turn, provide the earlierdescribed visual cues through oppositely disposed molded light pipeassemblies 212 and 214. The lenses of these assemblies extend throughcorresponding linearly arrayed openings. For example, the lenses of thelight pipe array 212 extend through the openings identified at array 60for right housing side 16. A similar arrangement is provided withrespect to left housing side 18 and light pipe array 214. Two outwardlyprotruding dimples as at 216 and 217 are molded in the housing inadjacency with the connectors as at 36 and 152. These dimples facilitatethe positioning of the flexible conduit 34 extending from the suctionmanifold 26 under a connector platform. Finally, FIG. 3 shows an inputassembly for the cable 62. This is a molded plastic component whichfunctions to introduce fourteen leads into the housing 14. Thecomponent, shown at 218 is over-molded with a flexible plastic toprovide stress relief for the cable 62.

[0125] Referring to FIG. 4, a sectional view is presented illustratingthe operative association of the motor drive features with thedisposable support housing 110 contained components. In the figure, themotor assembly 170 is seen to be located within motor mount chamber 160.As noted above, in that chamber 160, the assembly 170 is permitted someself-aligning movement but is restrained from rotational movement by thetorque stop component 172. The output from the planetary gear assembly170 b is coupled to the driven input side of coupler 174 which is seento extend through a taurus-shaped fluid seal 220 located within the sealchamber 162 defined by oppositely disposed and spaced apart bulkheads222 and 224. Note that the flexible seal does not constrain the coupler174 and permits the noted self-alignment of the motor assembly 170 withrespect to the elongate threaded translation component 176. Thatcomponent is seen extending to the thrust bearing 178. Bearing 178provides support against all of the driving forces imposed from themotor assembly 170 as it drives the transfer assembly 180 from thetranslation component 176. The figure reveals that the driving surfaces226 of the Y-shaped yoke 184 engage the tabs or ears as at 134 to urge adrive component forwardly as is described in connection with FIG. 6.

[0126]FIG. 4 also reveals some details of the tip 32 of delivery cannula22. That tip 32 is depicted as it is utilized for relatively smallertissue volumes, for example, encompassed within a diametric extent ofabout 10 mm. The tip incorporates four precursor electrode componentsarranged in a cross shape or symmetrically about longitudinal axis 58.Two of the electrosurgical cutting portions of the precursor electrodesare revealed at 228 located just forwardly of a truncated cone-shapedceramic(alumina) protective tip 230. Tip 230 functions to provide anarc-resistant or arc isolating tip portion preventing its' breakdown.Located at distal end 32 are five smoke/steam collection or suctionintake ports as are represented at 35. Just behind these ports 35 is ablocking rib or ring 37 which functions to block any migration of steamor smoke along the outer surface of delivery cannula 22. The edges ofports 35 are positioned about 0.2 inch from ceramic tip 230 and have adiameter of about 0.08 inch. Rib or ring 37 may be about 0.050 inch wideand about 0.050 inch radially high.

[0127] The actuator and transfer assemblies which are mounted within thehousing 15 are more clearly depicted in connection with FIGS. 5 and 6.Looking to those figures, the motor assembly 170 is seen to be comprisedof a d.c. motor 170 a having a 3.2 watt assigned power rating marketedunder the catalog designation 118686 by Maxon, Precision Motors Inc., ofBurlingame, Calif. This motor 170 a is combined with planetary gear head170 b exhibiting a 29:1 reduction and marketed under the catalogdesignation 118185 by Maxon Precision Motors Inc. (supra). The outputshaft of the gear head 170 b is shown at 232 and is seen to extendthrough the torque stop component 172. That component 172 is seen inFIG. 6 to be bolted to the forward casing of the gear head assembly 170b and is configured with a rectangular tab portion 234 which engages aslot 236 within housing 15 side 18. Motor assembly output drive shaft232 is fixed by a setscrew 238 into driving relationship with one sideof the cylindrical bellows coupler 174, which is surmounted in turn bythe flexible fluid seal 162. The opposite side of the bellows coupler174 is connected to the necked-down shaft 240 of the threaded elongatetranslation component 176. Fixed connection with component 176 isprovided by another setscrew 242 extending within bellows coupler 174.The opposite end or forward end of the threaded translation component176 as at necked-down shaft portion 244 is fixed to the thrust bearing178 and is rotatable therein. Nut component 182 of transfer assembly 180is shown threadably engaged with the translation component 176 and FIG.6 reveals that the yoke thereof at 184 extends upwardly such that it canengage the driven surfaces of the tabs or ears extending outwardly froma drive member located within the support housing 110 of the disposablecomponent 108 of the system. Note that the nut component 182 of transferassembly 180 is configured with a rearwardly disposed inwardly extendingchamber resembling a counter-bore and shown at 246. This chamber 246permits the nut component 182 to pass over a portion of the coupler 174and seat against a bulkhead surface 248 formed within the housing 14.When so seated against the bulkhead 248 surface, the transfer assembly180 is considered to be in a “home” position. During operation of theinstrument 12, the translation component 176 is rotated to drive thetransfer assembly 180 forwardly to effect a motorized driving of thecapture component of the instrument through a drive assembly. Such aforward movement is represented in FIG. 5 in phantom at 180. In general,the motor assembly 170 drives the transfer assembly 180 forwardly untila motor stall condition is encountered which represents a completion ofpursing activity or tissue volume capture. A control assembly associatedwith instrument 12 then recognizes the stall to carry out a motorreversal, returning the transfer assembly 180 to the noted home positionwhich is recognized by a reverse stall characteristic at the motor 170a.

[0128] Because the instrument 12 will be used by practitioners who areboth right handed and left handed, the components forming it are madesymmetrical as evidenced by FIGS. 7 and 8. Looking to those figures, itmay be observed that actuator switches 54-56 are centered betweenhousing 14 halves 16 and 18 and that the light pipe structures extendingfrom printed circuit board 210 (FIG. 3) mounted light emitting diodesextend to the bottom of each housing half to provide LED implementedvisual cue arrays as represented by array 60 and by array 250. Assuranceof a proper insertion of the disposable support housing 110 and itsassociated delivery cannula 22 is provided by the noted indexing pin 116and elongate slot 118. To assure proper alignment, a red dot ispositioned on the former component as well as above the aligning slot asshown at 252 in FIG. 8. FIG. 9 shows an orientation of the stabilizergrip 52 for use by a right handed practitioner having a relativelylarger hand structure as represented in phantom at 254. For thisarrangement, the stabilizer grip 52 is positioned somewhat rearwardly onconnector 152. FIG. 10, on the other hand, shows a more forwardorientation of the stabilizer grip 52 for a left handed practitionerwith a relatively smaller hand as represented in phantom at 256.

[0129] As revealed in FIG. 11, the grip connectors as at 36 and 152 alsocan be utilized in conjunction with pistol grip style stabilizers. Inthis regard, a pistol grip is shown in FIG. 11 at 258 having a slot (notshown) engaging the platform 154 extending over pedestal 156. Grip 258is retained in position by a bolt 260 which engages the indentationswithin platform 154 (FIG. 7).

[0130] The disposable or replaceable component 108 with support housing110 and delivery cannula 22 is illustrated in detail in connection withFIGS. 12 and 13. Support housing 110 is formed of two identically moldedhousing halves which are joined together and additionally interconnectedwith the delivery cannula 22, threaded connector 24, and the smoke/steamexhausting suction manifold 26 which is connected with suction tube 34.The embodiment of these figures shows the distal tip 32 at the forwardregion 30 of the delivery cannula 22 to incorporate a pair of polymerictip components 264 and 266, the latter component providing a rampstructure for the leafs of a capture component retained within theforward region 30. Two of the four components of a forwardly extendingprecursor electrode are shown in these figures in the manner asdescribed in connection with FIG. 4. In general, the freely rotatablesuction manifold 26 is retained in position over the cannula 22 bycollar 28 and the entire rod-like delivery cannula 22 is covered with anelectrically insulative shrink wrap 269 (FIG. 18) which terminates at aunion represented at line 268.

[0131] Referring to FIG. 14, a sectional view of the support housing 110is revealed showing its formation from two identical moldings 270 and272. Note that moldings 270 and 272 are retained together at theirforward portions by connector 24 which, additionally, supports thedelivery cannula 22. Cannula 22 is seen to be a hollow tube and extendsthrough an evacuation chamber 274 formed within freely rotatablemanifold 26. It further may be observed that the delivery cannula 22 isformed with a hole or aperture 276 such that vacuum can be communicatedfrom the tubing 34 into the chamber 274 and thence along deliverycannula 22 toward its tip or distal portion 32. At the opposite end ofthe molding components 270 and 272, the earlier-described indexing pin116 is adhesively attached within a molded slot, the corresponding openslot in component 272 being seen at 278.

[0132] Extending from a rearward bulkhead represented generally at 280and defined by molded components of support housing 110 moldings 270 and272, there is provided an elongate support tube 282. Tube 282 is formedof stainless steel and is anchored at the rearward side of the bulkhead280 by a plastic collar 284 adhesively bonded thereto. Support tube 282extends symmetrically along longitudinal axis 58 to be outwardly flaredfor engagement with forward tip component 266 (FIG. 12).

[0133] Looking additionally to the enlarged representation of FIG. 15,it may be observed that, extending through the interior of the supporttube 282, is a stainless steel precursor electrode tube 290 the rear tipof which extends along axis 58 into engagement with the paired moldingcomponents 270 and 272 at cavity 292. That portion of the precursorelectrode rod 290 which extends rearwardly from support tube 282 isconfigured with an electrically conductive surface which receiveselectrosurgical precursor electrode current through resiliently biasedterminal component 120. The remainder of the precursor electrode tube290, as it extends within support tube 282, is covered with anelectrically insulating shrink wrap seen in FIG. 15 at 294. It may berecalled that the terminal 120 lower disposed wiping surface engagescorresponding contacts distributing electrosurgical cutting current inthe vicinity of cable clamp 190 as described in connection with FIGS. 3and 4. This component 190 also serves as an electrically insulatingbarrier to isolate electrical contacts (at high RF voltage) from motorassembly 170.

[0134] Five, nineteen-strand, braided stainless steel cables extend fromtheir connection with the capture component of the instrument located atforward region 30 to a polymeric cable terminator component which isslidably mounted over the support tube 282 and moveable thereon inparallel with the longitudinal axis 58 of the instrument. Two of thebraided pursing cables are stylistically represented in the drawing at300 and 301. However, all five of these cables extend to and areconnected with the cable terminator component 296. Looking additionallyto the sectional view at FIG. 16, the terminator component 296 is seento be formed with five longitudinally disposed and radially spacedchannels 306-310 into each of which one of the cables as at 300-301extend. In this regard, cable 300 is seen extending through channel 307.All five cables are retained or fixed to the terminator component 296 bytwo stainless steel collars. In this regard, a forward stainless steelcollar or ferrule 312 is press-fitted over the five cables following apoint-in-time of fabrication wherein they have been positioned throughthe channels 306-310 and retained in uniform, balanced tension fromtheir engagement with the forwardly disposed capture component assembly.Uniform tensioning of the five cables is essential to a symmetricalpursing action and symmetrical cage structuring of the capture componentat its forwardmost location. With appropriate tensioning, both theelectrically conductive collar 312 and a rearwardly disposedelectrically conductive stainless steel ferrule or collar 314 arerigidly press-fitted or attached over the five cables. Collar 314additionally functions to apply electrosurgical cutting power or currentsimultaneously to all five of the cables and, accordingly, it is nickelplated and then gold plated (by way of example, 5 micro inch and 20micro inch, respectively) such that electrosurgical cutting current maybe applied to it through a solder union 316 connecting the collar 314with a braded multi-strand and highly flexible insulated copper cable318. Cable 318, in turn, is soldered (or welded) to the forwardelectrical terminal assembly 122 at a solder union seen in FIG. 15 at320. As in the case of terminal 120, terminal 122 also engages a currentdelivery terminal within the housing or reusuable housing component 15.

[0135]FIG. 16 further reveals the presence of two guidance components orears extending outwardly from the cable terminator component 296. Theseears or guidance components are shown at 124 and 128 within respectiveslots 126 and 127. With the arrangement, as the five cables areelectrically excited with electrosurgical cutting current they are drawnin tension forwardly in the sense of the instrument to, in turn, pullthe cable terminator component 296 in attachment with cable 318 inslidable fashion forwardly over the support tube 282. This slidingmovement under the drive of cable tension continues until the cableterminator component 296 encounters and engages a cable stop 322 which,as seen in FIG. 14 is fixed to the support tube or rod 282 at a locationwhich is selected to establish the maximum diametric extent of openingand overall length of the containment structure or cage generated by thecapture component. This is the only adjustment or election required fordeveloping a variation in such diametric extent and length dimensioning.For example, that diametric extent will range from about 10 mm to about40 mm. As the cable terminator component 296 engages stop 322, the fivecables continue to be stressed in tension to an extent causing thepursing activity of the electrically excited cables at the leading edgeof this capture component.

[0136] Returning now to the drive assembly under which the five cablesare drawn in tension, FIG. 14 reveals a drive assembly whichincorporates a drive member 324 which is connected to an elongate drivetube or drive rod 326. Drive tube 326 is slidably mounted over supporttube 282 and extends forwardly through the delivery cannula 22 intowelded engagement with a pentagonally cross-sectionally configured leafassembly of the capture component at forward region 30. The five pursingcables 300-304 pass through this drive member 324. FIG. 17 reveals fivechannels for slidably passing the five pursing cables rearwardly totheir attachment at cable terminator component 296. Note that cable 300is shown stylistically extending through channel 330 in FIG. 14. Drivecomponent 334 is configured having two oppositely outwardly extendingears or driven engagement portions which are actuated forwardly by themotor assembly 170 drive imparted to the yoke 184 (FIG. 3). These earsor tabs as shown at 134 and 136 slide in alignment within correspondingrespective drive slots 130 and 132 formed within the support housing110. As the drive component 324 and attached drive tube 326 are drivenforwardly in parallel with the axis 58, the leafs of the capturecomponent commence to emerge from the forward region of the 30 of thedevice and drive component 324 will pass across either one or possiblytwo oppositely disposed resilient latches of a latch assembly as seen at336 and 338. As a consequence of passing over and beyond resilientlatches 336 and 338, the drive component and associated drive tube orrod 326 cannot be manually retracted rearwardly further than the forwardportion of latches 336 and 338. This will be seen to provide a manuallyretractable arrangement for the drive member wherein the capturecomponent can be adjusted to open only to a limited extent making anopen cup-shaped access to the biological sample available from stablecontainment and easily off-loaded.

[0137] A drive safety stop mechanism or member 328 is fixed to thesupport housing to limit the forward movement of drive member 324 beyonda location representing a full pursing or contracting of the capturecomponent for the elected maximum diametric extent of capture. Suchunwanted movement may occur, for example, with a failure of cable stop322 to hold forward movement of cable terminator component 296. Fornormal operation, the drive member 324 ultimately will reach a locationin spaced adjacency with safety stop member 328.

[0138] Referring to FIG. 18, the forward region 30 and tip 32 of thedelivery cannula 22 are revealed in sectional detail. In the figure, thedelivery cannula 22 is seen extending forwardly to the earlier-describedpolymeric (e.g., polyetherimide) tip component 264. Delivery cannula 22is electrically insulated with a 5 mil thick polyolefin shrink tube 269extending to the earlier-noted border 268 at component 264. Next inboardfrom the internal surface of the delivery cannula 22 are five capturecomponent leafs in a pentagonal configuration, two of which are seen inFIG. 18 at 340 and 342. Extending next inwardly inboard is theearlier-described support tube 282 which is seen to extend to tip 32 andis flared at region 346 in addition to being adhesively coupled to thetip component 266. This flaring is found to be helpful in permitting thesupport tube to overcome the rather substantial forwardly directedforces occurring during the forward deployment of the capture componentleafs and cables. Extending inside the support tube 282 is theearlier-described precursor electrode tube 290 which, in turn, for theinstant diametric capture embodiment, supports a precursor electrodeassembly which comprises four precursor electrodes extending forwardlyof the ceramic cap 230, three of which are revealed at 228 a-228 c. Theprecursor electrodes are mounted as a subassembly of four stainlesssteel electrode wires having a generally elongate L-shape, including anelongate shank region or shaft, two of which are shown in conjunctionwith electrodes 228 a and 228 b at 348 a and 348 b. Four such electrodeassemblies are crimped inside of tube 350 and that tube 350, in turn, iscrimped within the forward portion of the precursor electrode tube 290.It has been found that the utilization of four cutting surfaces for theelectrodes, arranged in quadrature, provides preferable instrumentpositioning results. Such an arrangement of confronting electrodesurfaces is revealed, for example, in FIGS. 25 and 26. Sections of theshank regions of these precursor electrodes are seen in FIGS. 19 and 20at 348 a, 348 b, 352 a and 352 b. In general, the severing portions ofthe precursor electrodes will be extending normally to the longitudinalaxis of the instrument and will be configured to directly confront thetissue being severed during the insertion or placement of the instrumentin a confronting relationship to the involved tissue volume. Thedimensional extent of the confronting severing portions of theseprecursor electrodes is selected to provide an effective length lessthan the corresponding maximum diametric extent developed by the capturecomponent. In FIG. 18, that extent may be observed at stylized dashedlocus of movement line 354. In deploying the capture component, theforward or leading edge thereof containing the noted cables will cut apath somewhat similar to that shown at dashed line 354, reaching thecapture component predetermined maximum peripheral diametric extent atthat point in the deployment when pursing commences as the cableterminator 296 engages the cable stop member 322 as described inconjunction with the FIG. 14. By assigning one cable for each of theleafs that are utilized with the capture component, it has been foundthat an almost hemispherical curvilinear path of enveloping closure willbe defined as represented by the forward portion of dashed line 354encapsulating a tissue volume including a target tissue volumerepresented symbolically at dashed line 356.

[0139]FIG. 18 further illustrates the smoke-steam evacuation ports 35which communicate in vacuum association with an evacuation channelestablished initially as a gap between the outer surface of leafs300-304 and the internal surface of tip component 264. The channel thenextends rearwardly as a gap adjacent to internal surface of deliverycannula 22 to the suction manifold 26 (FIG. 2).

[0140]FIG. 19 reveals a section through the polymeric tip component 264.That component functions as a confinement or alignment sleeve for eachof the five leafs 340-344. The figure further reveals that a cable guideis provided as an elongate flexible polyamide cable guide tube extendinglongitudinally along the center at the outside surface of each leaf.These guide tubes for leafs 340-344 are represented respectively at360-364. Note that each of these tubes 360-364 is slidably locatedwithin a receiving chamber shown respectively at 370-374 which extendswithin the alignment sleeve 264. FIG. 19 further reveals that the leafstructure of pentagonal cross sectional configuration is connected, forexample, by laser welding to the end of the drive tube 326 (FIG. 14).

[0141] Sleeve 264 directs each of the five leafs of the capturecomponent into slidable engagement with a designated ramp locatedsomewhat rearwardly within the tip component 266. Thus, sleeve 264 andtip component 266 cooperate to provide a guidance assembly representedgenerally at 267. Each of the leafs is configured with a perpendicularlyoriented tip carrying two eyelets, a larger inner one slidably receivingan associated cable and a smaller opening or aperture for receiving andsecuring the knotted end of a cable. The five ramps established by thetip component 266 are revealed in FIG. 20 at 380-384 providing exitguidance for respective leafs 340-344 as they are urged forwardly by thedrive tube 326. In general, ramps 380-384 provide an angle of attack forthe individual leafs of about 45° with respect to the longitudinal axisof the instrument. The normally oriented, dual eyelet containing tips ofleafs 340-344 are shown in FIG. 20 respectively at 390-394. Note thatcable 300 emerges from guide tube 360, passes slidably through theinward eyelet of leaf tip 390 and is secured to the outer eyelet of tip394. In similar fashion, pursing cable 301 emerges from guide tube 364to slide through the inner eyelet of tip 394 and thence to be secured tothe outer eyelet of tip 393. Cable 302 extends from guide tube 363 toslidably pass through the inward eyelet of tip 393 and thence is securedto the outward eyelet of leaf tip 392. Cable 303 emerges from guide tube362 to slidably pass through the inward eyelet of leaf tip 392 andthence is secured to leaf tip 391. Finally, cable 304 emerges from guidetube 361, whereupon it slidably passes through the inward eyelet of leaftip 391 and is secured to the outer eyelet of tip 390. As noted above,the assigning of one cable for each leaf in the manner thus disclosedprovides a highly desirable rapid hemispherical closure of the capturecomponent in the manner illustrated by the forward portion of thestylized locus of movement outlined at dashed line 354.

[0142] While appearing somewhat complex at first observation, thepentagonally associated leafs, associated cables, and polymeric guidetubes or conduits of the capture component are fabricable at costscommensurate with the disposable nature of the component 108 withsupport housing and associated delivery cannula. For the capturecomponent to perform, it must emerge from the guidance assembly 267alignment sleeve 264 and an associated tip 266 ramp unconstrained untilit reaches that condition wherein the cable associated with it moves nofurther. At that juncture, the leaf leading edges commence to define aclosing or pursing hemispherical locus of movement. Individual leafs aresomewhat diminutive, being chemically milled from stainless steel with awidthwise extent selected to impart a lateral stability as well asflexibility during their outward movement. With such select structuringany warping away from the desired hemispherical pursing activity isavoided. This pursing activity forms a generally curvilinear cageperiphery which may be defined within planes parallel with thelongitudinal axis of the instrument. Stability with respect to thesomewhat transverse forces involved during the retraction or pursingaction of the cables also is achieved with the selection of leafthickness and width, consideration also being given to requisite leafflexibility.

[0143] For the instant leaf embodiment, a stainless steel implementedsequence of five leafs having a thickness of about 0.003 inch to about0.005 inch and a widthwise extent of about 0.080 inch is utilized.Construction of this pentagonal embodiment of the assembly of leafs isillustrated in connection with FIGS. 21-25. To form the leaf structurerepresented generally at 400, the stainless steel material (ss 304) ischemically milled to define each of the leafs 340-344 within flatstainless steel stock. In this regard, both the central trough orretainer groove to which the polyamide tubing is connected as well asfive longitudinal bend lines are chemically milled. Looking to FIGS. 21and 22, the base portions 339 of leafs 340-344 are seen to have beenbent and positioned about drive tube 324, such bending having takenplace at the milled bend lines 402-406. to define a polygonal tubestructure base. The tube structure is completed with a butt or lap formof weld located rearwardly of a trough or groove, for example, atlocation 407. This assemblage is then laser spot or tack welded alongthe inside center regions rearwardly of each leaf 340-344. Points oftangency between drive tube 324 and the leaf inside surfaces at whichsuch tack welding takes place with respect to the pentagonal structurerearward of leafs 340-344 are represented at respective positions410414.

[0144] After to the bending and welding procedure forming the pentagonalstructure of FIG. 21, the cable guides or polyamide tubes are attachedto the forward portions 345 of the leafs as seen at 360-364 in FIG. 22.Tube 360 is shown in FIG. 23 in connection with blade 340. At thisjuncture of fabrication, the dual eyelet containing tip 390 of blade 340has not been bent into a perpendicular orientation. Note that each tipas at 390 has an inwardly disposed pursing eyelet as at 386 and anoutwardly disposed connection aperture 387 of lesser diametric extent.Polyamide tube 360 initially is adhesively attached to the chemicallymilled trough or groove formed along the middle of one side of each ofthe blades as at 340. Then, as revealed at the sectional view at FIG.24, tube 360 is bonded to leaf 340 within the chemically milled grooveutilizing an electrically insulating coating material and process whichachieves bonding and provides requisite electrical insulation, and stillpermits necessary flexing of the blade. The coating, which has athickness of about 0.001 inch, is shown in FIG. 24 at 416. Coating 416is a vapor-phase-polymerized conformal coating marketed under the tradedesignation “Parylene”. Parylene is the generic name for members of apolymer series. The basic member of the series, called Parylene C, ispoly-para-xylene, a completely linear, highly crystalline material. Suchcoatings are available from Paryiene coating service companies such asSpecialty Coating Systems, of Indianapolis Indiana. For the instantpurpose, this coating will have a thickness ranging from about 0.0002inch to about 0.003 inch and, preferably, about 0.00075 inch to 0.00125inch. A significantly desirable bonding is achieved with this approach.These guide tubes are quite small, having, for example, an outsidediameter of about 0.020 inch and a wall thickness of about 0.0015 inch.The pursing cables extending within the guide tubes have a diameterwithin a range of about 0.002 inch to about 0.020 inch and preferably ofabout 0.005 inch. The guide tubes may be formed of other materials, forexample, a metal. When so fashioned the tubes may be formed or cut, forinstance, in spiral fashion or the like to promote flexibility. Theelectrically insulative coating applied to the leafs and guide tubesmay, for instance, be provided as a vitreous or polymeric material. Asanother step in the formation of the capture component assembly 400, thetips of the leafs are bent to a perpendicular or normal orientation withrespect to their widthwise extent. This is illustrated in conjunctionwith leaf 340 and tip 390 in FIG. 25.

[0145] Of course, the Parylene coating as at 416 electrically insulateseach of the capture component leafs such that the cutting action at theleading edge of the capture component is essentially only through thefive stainless steel pursing cables. Cables 300-304 remain electricallyinsulated as they extend through the insulatively coated and adheredpolyamide tubes shown in FIG. 22 respectively at 360-364.

[0146]FIGS. 26 and 27 present front views of the delivery cannula 22 tipregion 32, illustrating in particular the orientation of the precursorelectrodes, as well as the leafs and cables in a retracted state in FIG.26 and as the leafs and cables emerge in FIG. 27. As the leafs are beingdeployed, the pursing cables 300-304 are receiving electrosurgicalcutting current. In FIG. 26, the forward cutting portions of theprecursor electrode pair 228 a and 228 b are shown and arrangedperpendicularly thereto in quadrature are the corresponding forwardcutting surfaces of electrode 228 c and 228 d. In the figure, the fiveleaf tips 390-394 are visible in connection with portions of the pursingcables 300-304. For the orientation shown, the precursor electrodes 228a-228 d will have been excited while the instrument 12 is maneuveredinto an orientation wherein the tip 32 is in a confronting relationshipwith the targeted tissue volume. The precursor electrode structure thenis deactivated and the capture component is deployed in conjunction withthe excitation of pursing cables 300-304 with electrosurgical cuttingcurrent. Note that these pursing cables 300-304 are “playing out” alongthe leaf tips 390-394 and the effective diametric extent of the assemblyis expanding to circumscribe the targeted tissue volume to be removed.

[0147] In general, the precursor electrodes 228 a-228 d will have atissue cutting and confronting length of about 6.5 to 7.0 mm foremployment with a maximum effective capture diameter for the capturecomponent of 10 mm. Similarly, where that effective diameter expands to20 mm, the expanse of the precursor electrodes or their lengthwiseconfronting extent will be about 10 mm. As the diametric expanse of thecapture component and the length of the precursor electrodes increasesthe electrosurgically excited pursing cables will necessarily physicallycontact the open-circuited flexible precursor electrodes and reenergizethem as they are urged into alignment with the capture component leafs.This temporary re-energization of the longer precursor electrodes isfound to be beneficial as the electrodes retract or bend into largertissue samples being captured.

[0148] For applications of system 10 wherein magnetic resonance imageguidance is employed for tip positioning, the precursor electrodes,capture component leafs, pursing cables and the delivery cannula may beformed of non-ferromagnetic materials such as titanium or nitinol.

[0149] Referring to FIG. 28, the partial sectional view presented inconnection with FIG. 14 is reproduced, however, the drive member 324 isshown to have been advanced to a location wherein the cables 300-304will have drawn the cable terminator component 296 just into adjacencywith the cable stop 322. Stop 322, for the instant demonstration, islocated to establish an embodiment providing for a capture componenteffective maximum diametric extent, for example, of about 10 mm. Noteadditionally that the multi-strand flexible copper cable 318 has beendrawn forwardly by virtue of its connection with the cable terminatorcomponent 296. For the illustrated orientation of components 296 and322, the leafs and associated cables of the capture component will be atan extended location just prior to the commencement of a pursing actioncarried out by a tensioning of the pursing cables. For clarity, twooppositely disposed symbolic leaf structures are shown in the drawing at418 and 419 to illustrate the effective maximum diametric extent as thecapture component commences to purse about a tissue volume representedin phantom at 420. This effective maximum diametric extent as thussymbolically represented, is identified by the dimension indicatingarrows 422 along with the effective maximum capture diameter symbol: Dc.Also, the longitudinal distance between the forward surface of ceramictip 294 and the center of the tissue volume 420 is labeled as: L_(s)This distance, L_(s), also corresponds with the position of extension ofthe capture component leafs at which cable tensioning for the pursingmaneuver commences. The distance is that selected by the practitionerfor the initial positioning of the delivery cannula tip 32 using theprecursor electrodes. In general, the distance, L_(s), is selected asabout 0.6 D_(c). It further may be observed that the drive component hasbeen driven under the influence of the motor assembly 170 forwardly ofthe resilient one-way latches 336 and 338.

[0150] Referring to FIG. 29, the components described in connection withFIG. 28 again are reproduced, however, the drive member 324 andassociated drive tube 326 are shown to have been driven furtherforwardly. Cable terminator component 296 has remained in abuttingengagement with cable stop 322. This has caused a tensioning of the fivecables 300-304 and a pursing encapsulation of the target tissue 420 asrepresented by the symbolic leaf structures 418 and 419. The illustratedcables 300 and 301 are symbolically represented as being under stress ortight and, while the maximum effective diametric extent represented bythe dimensioning arrows 422 and the label, D_(c), remain substantiallyconstant, the capture assembly has, indeed, “captured” or encapsulatedthe targeted tissue volume 420 along with an amount of surroundinghealthy tissue. Note that the pursing ends of the leaf structures asrepresented at 418 a and 419 a have been tied together by an array offive cables under tension extending back to the cable terminatorcomponent 296. In effect, a structural containment arch-form is evokeddefining a forward curvilinear cross section resembling that of ahemisphere. This provides for protection for the tissue sample asdelivery cannula 22, which is of relatively small diameter andnoninvasive, is withdrawn with a stretching of tissue adjacent thecapture component or containment structure but with structuralprotection of the encapsulated tissue volume. Thus, a noninvasive natureof the retrieval is achieved without physical impairment even though arelatively larger tissue sample is removed.

[0151] Returning momentarily to FIG. 4, when the five cables 300-304have been stressed at the level associated with a fully carried-outpursing as described in connection with FIG. 29, the control over motorassembly 170 recognizes a resultant forward stall condition and reversesthe motor drive assembly output, and consequently, the output of thetranslation component 176, to return the transfer assembly 180 to its“home” position as described in connection with FIG. 5. However, ears134 and 136 extending outwardly from the drive member 324 now have beenreleased at their forward position from engagement with the yokecomponent 184. (See FIG. 6). Accordingly, when the disposable components108 of the instrument 12, including the support housing 110 and deliverycannula 22 have been removed from the reusuable housing 14 with thetissue volume retained within the capture component as shown in FIG. 29,the practitioner may then manually return the drive component to aposition against latches 336 and 338. Referring to FIG. 30, thisarrangement is illustrated. Drive member 324 and coupled drive tube 326have been manually moved rearwardly until the member 324 engages theinwardly extending components of the resilient latches 336 and 338. Thismanual retraction of drive member 324 by the practitioner has, in turn,retracted the five leaf structures as represented symbolically at 418and 419 such that their tips, as shown respectively at 418 a and 419 a,have returned rearwardly to define an open ended tissue sample cup foraccess to and/or transporting the targeted volume of tissue 420 andsurrounding healthy tissue represented in phantom at 422 for pathologyinvestigation. For this orientation of the components, the cables asrepresented at 300 and 301 again are symbolically represented as beingun-tensioned.

[0152] A salient feature of the invention resides in a structuring ofthe capture component and associated actuating system in a mannerwherein the effective maximum tissue circumscribing diametric extent canbe varied with the expedient of merely moving the cable stop component322 to different locations along the longitudinal axis of theinstrument. It may be recalled that the collar-shaped cable stopcomponent 322 is mounted upon support tube 282. This alteration ofcapture component diametric extent is illustrated in connection withFIGS. 31 and 32 in association with a target tissue volume shown inphantom at 424. Comparing FIG. 31, for example, with FIG. 28, note thatthe cable stop member 322 now is positioned forwardly toward thelatching components 336 and 338. The cable terminator component 296 isrepresented as having been drawn by cables 300-304 (here shownsymbolically at 300 and 301) to adjacency with stop member 322. Drivemember 324 and associated drive tube 326 have been moved forwardly withrespect to their corresponding position shown in FIG. 28. Thus, theleafs are moved mutually outwardly to a greater extent. The result is anenlarged capture diameter. Symbolic leafs 418 and 419 are represented inFIG. 31 as having been expressed to develop an effective diametricextent, as defined at their respective tips 418 a and 419 a, surmountingthe target tissue volume 424. This effective diametric extent issymbolically represented by the arrow pair 426 and symbol, D_(c). Forthis embodiment achieving -a capture diametric extent of greater value,an expanded precursor electrode assemblage is called for to the extentthat the captured or encapsulated tissue volume may be readily removed.In general, the lengthwise extent of each of the wire components of theprecursor electrodes will be less than the effective maximum diametricextent of the capture component as it is expressed to the commencementof cable pursing activity as represented in FIG. 31. As before, fourprecursor electrode components are employed, two of which are shown insolid line fashion at 428 a and 428 b. These precursor electrodes 428 aand 428 b are coplanar and arranged normally to a corresponding pair ofsuch electrodes. With the arrangement shown, following the positioningof the tip of the delivery cannula 22 in confronting adjacency with thetarget tissue volume 424, electrosurgical cutting current is terminatedat all precursor electrodes including those at 428 a and 428 b, thecutting drive circuit, in effect, being open circuited at a high voltageoutput stage 520 shown in FIG. 34. However, when the pursing cablescommence to emerge from delivery cannula 22 at the tip component 266 inconjunction with capture component leaf movement, they will encounterthe somewhat flexible electrode wires of the precursor electrodes, asshown for example at 428 a and 428 b and re-excite them withelectrosurgical cutting current. These electrodes then will be bentforwardly into the tissue sample volume as they are so re-excited toassume the orientations shown in phantom, for example, at 428 a′, 428 b′and 428 c′. In the latter case, the precursor electrode 428 c′ is, asnoted, perpendicular to or normal to the electrodes 428 a and 428 b. Afourth such electrode (not shown) coplanar with electrode 428 c′ will beflexed similarly from the opposite side of the capturing region by thepursing cables. As the pursing cables continue to move forwardly underelectrosurgical cutting current excitement, contact and electricalconduction with the precursor electrodes is terminated and the latterelectrodes are permitted to flex rearwardly to their originalorientations in planes through the longitudinal axis of the instrument.Thus, these precursor electrodes will be permitted to return through thetissue cutting paths evoked with their re-energization by the pursingcables.

[0153] Referring to FIG. 32, the orientation of the components ofcomponent 108 of instrument 12 are revealed as the drive component 324and associated drive tube 326 have been forwardly driven along thesupport tube 282 while the cable terminator 296 has remained instationary contact with cable stop 322. Accordingly, these symbolicallydepicted cables 300 and 301 are represented as being tight or understress induced by the pursing action carried out by the drive member 324subsequent to its orientation as shown in FIG. 30. Note that the tipportions 418 a and 419 a of the symbolically depicted leafs 418 and 419have been drawn together by the pursing action of the cables 300-304 andthus, a hemispheric, dome-like configuration has been evoked having theforward curvature shown. A comparison of this curvature with thatrepresented in FIG. 29 shows them to be quite similar in terms of degreeof curvature, a phenomenon evoked by virtue of the utilization of apursing cable in association with each of the leafs of the capturecomponent. This association has been described, for example inconnection with FIGS. 26 and 27 above. FIG. 32 also reveals that theprecursor electrodes as at 428 a and 428 b have resiliently returned toan orientation normal to the longitudinal axis of the instrument 12.With this arrangement, the volume of targeted tissue 424 as well as anamount of surrounding healthy tissue 430 may be withdrawn while beingprotected by the structural integrity now extant at the capturecomponent pursed together leafs which are retained in compression by thepursing cables, a state wherein they contribute to the formation of astructurally rigid containment structure cage. Referring to FIG. 33(below FIG. 11) the rear panel of the console 64 is revealed. That rearpanel supports a cooling fan represented symbolically at 432 positionedbehind a grill 434. The speaker which generates aural cues representingelectrosurgical cutting activity or a return electrode fault ispositioned behind a grill represented generally at 436. A volume controlknob performing in conjunction with a potentiometer is represented at438 beneath the grill 436. A.c. line input is provided at a receptacle440. A multi-channel footswitch input connector is provided at 442 and asuction system interlock connector is shown at 444 (see arrow 53 in FIG.1).

[0154] Referring to FIG. 34, a generalized block diagrammaticrepresentation of the electrosurgical generation features, controlassembly with motor controls, switching and the like is presented. Ingeneral, the electrosurgical inputs to the pursing cables 300-304 and tothe precursor electrodes of the instrument are provided at an operatingfrequency of about 350 KHz. However the operating frequency may beselected to be in the range from about 250 KHz to about 10 MHz. Forbipolar or quasi-bipolar instrument modalities as described in theabove-noted application for U.S. patent, Ser. No. 09/472,673, now U.S.Pat. No. ______ where the return electrode is located on the shaft ordelivery cannula of the disposable component just proximal to the distalend or tip, the operating frequency may be as low as about 100 KHz.Different capture component maximum diametric values and associatedlengthwise capture dimensions are based solely on the location of thecable stop 322 (FIG. 14). With that configuration motor assembly 170 mayperform in conjunction with a control which detects forward and rearwardstall conditions as well as other load characteristic conditions whichwill represent fault states. In the figure, a conventional A.C. lineinput is represented at line 450 as extending to an electromagneticinterference (EMI) filter represented at block 452. As represented atline 454 and symbol 456, the filtered output then is passed through afuse and into the front panel power on/off switch function representedat block 458. This switching function was described in connection withFIG. 1 at 82. Switch function 458 passes the filtered input to a powerfactor correcting boost converter as represented at line 460 and block462. Converter 462 rectifies the A.C. input to it to a d.c. current andboosts the d.c. voltage level to a regulated 380 volts d.c. while alsocreating a sinusoidal input current waveform which matches thesinusoidal input voltage waveform. This provides for a high power factorto reduce line current harmonics. Converter 462 provides an interimvoltage as a 380 volt d.c. bus as represented at lines 464 and 466. Theprovision of the power factor correction feature at block 462 derives avariety of beneficial attributes. Less current is drawn as compared toconventional electrosurgical generators and the device may be employeduniversally with power utilities on a worldwide basis. Of additionalimportance, converter 462 derives a pre-regulated interim voltage atline 464 which permits an optimization of a next following link inverterin the electrosurgical generator function. Line 466 functions to providea d.c. input to a primary and an auxiliary low voltage power supply(LVPS) as represented respectively at blocks 468 and 470 in conjunctionwith lines 472 and 474. Redundant low voltage power supplies areemployed in view of the criticality of the control system associatedwith the instrument 12. In this regard, a failure of a low voltage powersupply otherwise occurring without such redundancy could result inshutting down the entire control system at a point-in-time duringcritical intervals in the procedure at hand.

[0155] The regulated 380 volts d.c. at lines 464 and 466 also isdirected to a low voltage power supply represented at block 476 whichfunctions to provide a very specific motor voltage to the motor drivecircuitry as represented at line 478 and block 480. Control over themotor voltage, for example, at a level of around 10 volts is important,inasmuch as it is that voltage level which provides the proper rate offorward travel of the leafs and cable components of the capturecomponent. In this regard, the deployment of the leafs andelectrosurgically excited cables is measured in terms of millimeters persecond. Should the drive imparted be too rapid, the excited cables willpush against tissue and not cut properly which may result in a falsecapture stall based response on the part of the control system. Becausethe control system operates the motor drive 480 on a basis of detecting,for example, forward stall currents to determine the completion of apursing activity, accommodation is made for anomalies in the motor drivecaused by binding phenomena or the like wherein a forward stall would bedetected by the control system before the capture component had beenproperly actuated. Because the rate of advance of the leafs andassociated pursing cables is carefully controlled, it is known, forinstance, that any stall condition detected before a certain initialtest interval of time commencing with an initial motor activation wouldrepresent a drive malfunction. Instrument 12 or “handle connector” 67 isrepresented in the instant figure at block 482 which is showncommunicating motor drive inputs as represented by arrow 484 coupledwith the motor drive function at block 480. Control to the motor driverepresented at block 480 additionally is provided from a controlarrangement which includes control and drive circuit boards asrepresented at block 486 and dual arrow 488. In general, extension ordeployment of the capture component is within a rate range of about 1millimeter per second to about ten millimeters per second, andpreferably between about 2.5 millimeters per second and about 4millimeters per second.

[0156] Returning to line 464, the regulated 380 volts d.c. output of theconverter 462 is introduced to a 100 KHz link inverter represented atblock 490 which additionally is shown to be under the control of thecontrol and drive circuit board function of block 486 as represented atdual arrow 492. That control is called upon to effect a constant voltageregulation of the electrosurgical output energy, accommodating thenegative dynamic impedance of a cutting arc while achieving anarc-sustaining, non-oscillatory performance. The a.c. (squarewave form)output of inverter 490 is presented, as represented at line 494 to oneside of an isolation transformer represented at block 496. Transformer496 provides an output, as represented at line 498 which is rectifiedand filtered as represented at block 500 to develop a d.c. link voltageat line 502 having value of about 100 volts. The amplitude of the linkvoltage at line 502 is very well controlled and functions to modulatethe amplitude of the output of the system. Line 502 is directed to tworelay disconnects as represented at block 504. These relay disconnectsare controlled from the control and drive circuit boards 486 asrepresented by arrow 506. The d.c. link voltage then, as represented atarrow 508 is directed to an RF inverter as represented at block 510.Inverter 510 operates in controlled relationship with the control anddrive circuit boards represented at block 486 as indicated by arrow 512.It may be noted that by positioning the relay disconnects 504 ahead ofthe RF inverter 510, in case of a fault or other anomaly, input to theRF inverter 510 itself can be disconnected. Inverter 510 is of aconventional resonant or tank circuit variety which is tuned to aparticular frequency. Its output peak-to-peak voltage amplitude iscontrolled by the amplitude of the d.c. link voltage. Thus, while theoutput voltage amplitude is controlled to remain constant, its frequencyalso will remain consistent.

[0157] The output of inverter 510 is directed, as represented by line514 and block 516 to one side of a high voltage transformer which stepsits amplitude up to about 800 to about 1000 volts peak-to-peak fornormal (non-boost) cutting purposes from a 100 volt d.c. link voltagelevel. This output of the transformer stage 516 at line 518 is an arcgenerating electrosurgical cutting output which is, in effect, steeredby series relays at a high voltage output stage, represented at block520, to either the precursor electrode input as represented at arrow 522or to the capture component cables as represented at arrow 524. Controlover the stage represented by block 520 is indicated by arrow 526.

[0158] The control system also performs in conjunction with a patientcircuit safety monitor (PCSM) which is represented at block 528. Asdiscussed in connection with return electrode 68 in FIG. 1, the presentsystem operates in monopolar fashion and utilizes a dual componentdispersive pad as a return electrode. These two return electrodecomponents were described at 70 and 72 in FIG. 1. As represented at dualarrows 530 and 532 directed respectively to the R and R leads of thereturn electrode connector, a small high frequency current can bedirected from one pad as at 70 along the patient to the other as at 72(FIG. 1) to verify the tissue resistance between those pads. For theinstant illustration, the connector earlier described at 77 is shown asblock 534. Control for this monitoring procedure is represented at dualarrow 536 and the output of the test at block 528 is represented atarrow 538. The PCSM circuit 528 will apply about a ten volt signal at 50KHz to the two return electrode pads and verify proper resistance. Onlyupon such verification will the system permit the practitioner tocontinue the procedure by going into a ready mode. If the PCSM test isnot met or passed, the system will not proceed and both visible andaudible pulsed alarms are produced.

[0159] Also associated with the control and drive circuit boardsrepresented at block 486 is a front panel circuit board as representedat block 540 and arrow 542. That front panel circuit board performs inconjunction with the front panel controls described in connection withFIG. 1 as represented at block 544 and arrow 546.

[0160] The footswitch connector earlier described in conjunction withFIG. 33 at 442 is identified in the instant figure at a block carryingthat numeration. A three pair lead input from this footswitch connectoris symbolically represented by bus arrow 548. Inputs from the buttonswitches 54-56 of instrument 12 are represented at arrow 552, whileoutputs to the LED arrays as at 60 are represented at arrow 554.Finally, vacuum switch 51 is represented by a block with that sameidentifying numeration along with earlier described arrow 53 extendingto block 486. Arrow 53 represents a two lead input.

[0161] With the circuit arrangement thus described, a primary circuit isdeveloped between the A.C. input at line 450 and the isolationtransformer 496. From the output of isolation transformer 496, providingthe noted D. C. link voltage, a secondary, lower voltage circuit isevolved. That secondary circuit extends to the high voltage transformerrepresented at block 516. From that circuit location, a high voltagecircuit obtains with the system which develops the noted electrosurgicalcutting outputs. These three different circuit regions are incorporatedwith different isolation barriers of the system. In this regard, somecomponents fall within a safety extra low voltage circuit regime (SELV)while all other circuits are completely isolated from potential contact.For medical devices which are going to be attached to a patient,concerns become more stringent for assuring that no current will flowfrom one device, for example, to another associated with the patient.

[0162] Referring to FIG. 35, an isolation and insulation diagram ispresented which may be associated with the system diagram of FIG. 34. InFIG. 35, encircled insulation codes 1 through 7 are located. These codescorrespond respectively with the insulation types: BI, BOP, RI, RI, BI,RI, and OP. These insulation types are further identifiable as follows:

[0163] “OP”-operational insulation;

[0164] “BOP”-basic insulation between parts of opposite polarity;

[0165] “BI”-basic insulation providing the first level of protectionagainst electric shock;

[0166] “RI”-reinforced insulation.

[0167] Looking to FIG. 35, dashed boundary 560 represents the conductiveenclosure of console 64. A patient is symbolically represented at 562who will be contacted by the active electrode (AE) as represented atarrow 564 and return electrodes (RE) as represented at lines 566 and568. The nonconductive handle of the instrument 12 is represented atblock 570 and the cable and connector cover as represented at 62 againis identified with that numeration. A nonconductive front panel of theconsole 64 is represented at block 572.

[0168] A. C. input to the control system is represented by line, neutraland earth lines shown respectively at lines 574-576. This commences theearlier noted primary circuitry. Note that insulation code 1 extendsbetween line 574 and the chassis 500. Next, the primary circuit extendsto a transformer function represented symbolically at 578 and carrying aboundary code 3 which is a high voltage insulation boundary. Then atransition to about a 100 volt d.c. link voltage represented at line 580occurs with an isolation boundary code 4. The system then extendsthrough the RF inverter represented at block 582 to a high voltagetransforming function represented generally at 584 with an isolationbarrier code 5. This transforming function 584 develops the high voltageoutput as represented at line 586 in conjunction with an isolation code6. Note that return lines 566 and 568 extend through coupling capacitorsshown, generally at 567 to the output of transforming function 584. Nextthe system extends through blocking capacitors 587, front panel 572,cable 62 to instrument 12 with active electrode 564 and thence to thepatient 562. The return electrodes as represented at lines 566 and 568are seen associated with the PCSM circuit now shown at block 588 whichis further isolated at insulation barrier 5 before having operationalassociation with the low voltage control circuits represented at block590. These low voltage control circuits as at 590 are shown insulatedwith respect to the chassis 560 at code 4. Certain inputs to and outputsfrom this low voltage control are represented at bidirectional arrow 558extending across front panel 572, cable assembly 62 and instrumenthousing assembly 570. Footswitch function 86 is shown isolated fromcircuits 590 at transforming function 592 in conjunction with code 3insulation. Bus arrow 548 is reproduced extending to function 592.Similarly, vacuum switch 51 is identified by a dashed block along witharrow 53 which extends to transforming function 592. The +12 volt d.c.input to the circuits 590 as represented at lines 554 and 556 areisolated as represented at transforming function 594 which is associatedwith code 3 insulation. The d.c. link converter function represented atblock 596 is isolated from the low voltage control circuits 536 asrepresented by transforming function 598 in conjunction with insulationcode 3. PCSM function 588 is coupled with return lines 566 and 568 vialine pair 589 and is isolated by transforming function 600 from the lowvoltage control circuits, that isolating function being associated withan insulation code 5. Note additionally that code 7 insulation isassociated at the interface between the cable assembly 62 and instrument12 as represented at block 510.

[0169] Referring to FIGS. 36A and 36B, the system association of a mainpower circuit board, daughter circuit boards, the instrument, andperipheral components is revealed. These figures should be considered inthe manner labeled thereon. The earlier described EMI filter modulereappears with the same numeration at block 452 in FIG. 36B inconjunction with line and neutral inputs 610 and 612 extending to themotherboard or power circuit board represented at 614. Power board 614is shown to be operably associated by bus symbols 616, 618, and 620 witha “drive” printed circuit board represented at 622. Drive circuit board622 carries components for the earlier-described power converters, forexample, carrying out power factor correction, boost converting, D.C.link converting, the RF converter and low voltage power supplies.

[0170]FIG. 36A reveals another daughter circuit board referred to as a“control board” at 624. Control circuit board 624 incorporatescomponents controlling the commencement and termination of events atdrive board 622 and providing an interface with both the instrument 12and the front panel of console 64. Logic for sequencing events in thesystem is developed with a programmable logic device (PLD) mounted withthis control circuit board 624. General interfacing between the powercircuit board 614 and this control circuit board 624 is represented atarrow 626 and the return electrode signal lines 628 and 629. The handle(housing assembly 14) connector earlier described at 69 is representedat block 630. An association of the handle connector 630 with thecontrol circuit board is represented at arrow 632. That associationincludes the signaling employed with all housing assembly 14 mountedLEDs and switches. Handle connector 630 also receives motor control andelectrosurgical cutting inputs from the power circuit board 614 asrepresented at arrow 634.

[0171] Illuminating control to the power on LED 84 shown at FIG. 1 isprovided from line pair 636. Similarly, illuminating control over thegreen “handle” connector 67 LED 80 is provided from line pair 638.Finally, the illuminating control over the red LED 78 corresponding witha fault status at dispersive electrode 68 is provided at line pair 640from control circuit board 624. In general, where the PCSM test asdescribed at block 528 at FIG. 34 fails, the red LED 78 is pulseilluminated along with a pulsed aural alarm along with the imposition ofa system shutdown. The handle LED 80 is illuminated if an initialinterlock or connector test utilizing a small coding resistor within theinstrument 12 shows a proper connection.

[0172] A front panel daughter board is represented at block 642 which isassociated with the control board 624 as represented by arrow 644. Ingeneral, control is asserted as represented at arrow 644 to carry out acontrol over the LEDs at the upper region of console 64, including theindicator LEDs 94, 96, 98, 100, 102 and 104. Also, control over thestart switch 92 is provided from this line grouping 644.

[0173] Upwardly disposed in the figure is a speaker 646 which iscontrolled from the control board 624 via line pairs 648. Volume controlwith respect to the speaker 646 is provided by a potentiometer earlierdescribed at 438. Control from this potentiometer is developed at threeline array 650 extending to control circuit board 624.

[0174] Returning to the power circuit board 614 components, theconnector or harness associated with the return of dispersive electrode68 is represented at block 652. Its association with the power circuitboard is represented at line pair 654. Similarly, the wire harness orconnector from the principal footswitch 86 is represented at block 656.The six lead inputs from the footswitch 86 to the power circuit board614 are represented at bus 658. Similarly, the vacuum switch isrepresented at block 51 in conjunction with two lead arrow 53.

[0175] Front panel switch 82 is represented in FIG. 36B with the samenumeration. The switch 82 is operatively associated with components ofthe power circuit board 614 through a four line array 660. Finally, fan432 is represented by the same numeration in operative association withthe power circuit board 614 through paired control lines 662.

[0176] The discussion now turns to the functions and componentsassociated with power circuit board 614. These components are describedin connection with FIGS. 37A, 37B -43A, 43B, and 43C to follow. FIGS.37A and 37B should be considered in the manner labeled thereon. Lookingto FIG. 37A, line input is provided to the earlier described EMI filter452 which is reproduced in the present figure. Referred to as a “rearpanel power entry module”, the device 452 may be provided as a linefilter with A.C. inlet type 5110.1033.3 marketed by Schurter, Inc. of79343 Endigen, GE. The filtered output from device 452 is present atline, neutral and ground lines shown respectively at 664-666. Lines 664and 665 are directed to fuses and, as well as to components providingadditional EMI filtering. Those components include capacitors -, a dualinductor form of device, inductor and a discharge resistor. Furtherprotection is provided by varistors 668, 669 and capacitor. The filteredA. C. input then extends across the front panel power switch representedat 82 which, as described in connection with FIG. 36B, is accessed froma harness. In-rush current occasioned by the presence of relativelylarger hold-up capacitors in the system is controlled by a negativetemperature coefficient thermistor 670 extending across the contact :Bof a relay within line 674. Looking momentarily to FIG. 38, the solenoidactuating components of that relay are revealed at :A. This solenoidactuator performs in conjunction with a RELAY_IL control input at line908. Any inductive spikes occasioned by solenoid control are controlledby diode.

[0177] Returning to FIG. 37A, diode extending within line 676 from line674 and diode extending within line 678 from line 680 function to derivea rectified AC_SENSE signal in conjunction with a resistor within line682 and seen in FIG. 37B. The AC_SENSE signal at line 872 is utilized toderive an indication to the control that the input is of high enoughvoltage amplitude to operate the system.

[0178]FIG. 37B shows that lines 674 and 680 extend to a rectifier 684which derives a haversine waveform at lines 682 and 686. Rectifier 684may be provided as a type D25×360 marketed by Schindengen America, Inc.of Westlake Village, Calif. Small filter capacitors and extend betweenthese lines. The full wave rectified A.C. voltage is applied across thelatter capacitors to the input of the earlier-described power factorcorrection boost converter represented generally at 462 and comprised oftransistors and which perform in conjunction with principal componentsincluding inductor and diodes and under the switching control of acontroller driven driver represented at block 687. In this regard, notethat control line 688 extends from output A of the driver 686 to thegate of transistor to effect switching control thereof in conjunctionwith peripheral components including resistors and, diode, capacitor andbead . In similar fashion output B of driver 686 carries out switchingcontrol at the gate of transistor via line 690 in conjunction withresistors and, diode, capacitor and bead. Device 687 is controlled by aDRV_PFC signal at input line 692, receives primary circuit low voltageinput, +12V_PRI at line 694 and is configured in conjunction withcapacitors −1 and resistor. Device 686 may be provided, for example, asa type MI424 BiCMOS/DMOS buffer/driver/MOSFET driver marketed by Micrel,Inc. of San Jose, Calif. The earlier described pre-regulated 380 voltsacross lines 682 and 686 is applied across very large holdup capacitors2 and 3 which function to protect the system against vagaries such astransient sags and surges induced at the line input. In effect, thecapacitors provide energy storage to “ride through” such anomalies.

[0179] The figure also reveals an A.C. current sense signal (AC_I) atline 916 extending from line 682 which is associated with parallelresistors and. That signal is employed in conjunction with power factorcontrol (FIG. 44B) in association with a corresponding A. C. voltagesense signal, (AC_V) at line 686 extending from line 922 and a +380Vsignal at line 830. The circuitry thus far described represents theearlier-discussed primary circuit which subsequently extends to asecondary circuit upon passing the primary transformer function 496.

[0180] Looking to FIG. 39, an over-temperature switch, which is mountedupon a heat sink within the console 64 is represented at 696. Where anover-temperature condition exists, then the low logic true signal, TEMPis generated at line 697.

[0181] Referring to FIG. 40, the regulator for developing the importantmotor voltage input is shown at 698. Device 698 may be provided, forexample, as a type LM2941 Low Dropout Adjustable Regulator marketed byNational Semiconductor Corp. of Santa Clara, Calif. The device functionsin connection with a +12V input at line 700 and is configured inconjunction with capacitors 4-6 and resistors 0 and 1 to provide a motorvoltage output, V MOTOR at line 702.

[0182] As discussed above in connection with FIG. 34, the presentcontrol system includes two low voltage power supplies as described inconnection with blocks 468 and 470. These redundant power suppliesprovide logically ORed outputs. FIG. 41 reveals one of these identicalcircuits which is represented in general at 468 in consonance with thediscussion at FIG. 34. Circuit 468 taps the +380V high voltage output atline 704 incorporating fuse and which is directed to one end of theprimary side of a transformer. The opposite end of the primary side iscoupled to primary circuit ground ultimately provided from line 706.Switched control input to the input side of transformer is carried outby a control device or controller 706 which is configured in conjunctionwith capacitors 7 and 8, resistors 2-4 and diodes -0. Switching control706 is referred to as a “smart power switch” which incorporatesregulating circuitries including a power transistor along with PWMcontrol circuitry and the like. The device may be provided as a typeTOP234Y Integrated Off-Line Switcher marketed by Power Integrations,Inc., of Sunnyvale, Calif. Transformer provides galvanic isolation andits secondary is tapped at lines 708 and 709 to present a +12V low powersupply to ORing diode 1. That output is rectified by diode pair 2 andfiltered by inductor and capacitors 9-21.

[0183] Feedback control to the switching controller 706 is derived atthe secondary side of transformer at line 710 which extends to asecondary side input network represented generally at 712 and comprisedof resistors 5-8, capacitors 2 and 3 and diode 3. Network 712 provides avoltage proportional signal to the input diode of an opto-isolator 714.The output of opto-isolator 714 returns a feedback signal representingthe voltage level at line 708 to the primary circuit side of the powersupply by modulating an input from the connection with a second portionof the secondary side of transformer incorporating line 716, diode 4 andcapacitor 4. This signal is modulated at the opto-isolator 714 anddirected via line 718 to the control input of controller 706.

[0184] A variety of relays are employed for the purpose of motoractivation, safety and control over the dual electrosurgical cuttingsequences and the like. Referring to FIG. 42, a relay controller 720 isillustrated in conjunction with a sequence of five relay input controlsignals at its I-I input terminals. Device 720 may be provided as a typeULN2004 High-Voltage, High Current Darlington Array marketed by MicroSystems, Inc. of Worcester, Mass. The device 720 is configured with +12Vinput and capacitor 5 and functions to provide drive outputs to thesolenoid components of a sequence of relays. In this regard, relaysolenoid components :A and :A are connected with terminal OU and line722, thence to +12V. Solenoid components :A and :A are coupled betweenoutput terminal OU by line 723 and thence to +12V. Relay solenoidcomponents :A and :A are coupled with output terminal OU by line 724 andthence to +12V. Relay solenoid :A is coupled to output terminal OU vialine 725 and thence to +12V and relay solenoid :A is coupled withterminal OUTS of device 720 via line 726 and thence to +12V. The lattertwo solenoid actuators function to selectively actuate or driverespective dual relay contacts :B, :C and :C, :B to provide directionalcontrol to motor 170 a. The inputs to the contacts :B and :C are coupledwith the earlier described V_MOTOR input at line 728 and thecorresponding inputs of contacts :B and :C are coupled with line 730.Line 730 is seen to be coupled to secondary circuit ground inconjunction with resistor 9 and filter capacitor 6. A positive motordrive output, MOTOR+ is provided at line 732 and a negative or oppositepolarity motor drive output MOTOR_, is seen provided at line 733. Notethat line 734 couples the MOTOR+signal with one side of relay contacts:B and that line 735 couples line 733 with one side of relay contacts:C. Thus, energization of relay :A provides a forward motor drive, whileenergization of relay :A provides a reverse motor drive. Motor currentis monitored at lines 1060 and 730 to provide a signal, “MOTOR_I”, usedto evaluate the instantaneous motor current draw or load characteristic.

[0185]FIGS. 43A and 43B should be considered in accordance with thelabeling thereon. Referring to FIG. 43A, a more detailed illustration ofthe 100 KHz link inverter described at block 490 in connection with FIG.34 is revealed. The inverter is represented in general with that samenumeration. Inverter 490 is implemented in a unique manner forelectrosurgical applications, inasmuch as it is a “resonant transitionphase shift inverter” which evokes what may be termed “soft” switching,driving the primary side of main isolation transformer, earlierdescribed at block 496 in FIG. 34. The transformer is additionallyidentified with that earlier numeration. Inverter 490 is formed withMOSFET transistors -. Of these transistors, transistors and are switchedin complementary fashion as are transistors and. Because these switchingtransistors perform in the primary circuit domain in conjunction with380V extant at line 740 containing fuse and primary circuit ground aspresent at line 742, it is necessary to provide for a primary tosecondary circuit isolation between the control input to the inverter490 and the switching components of it. Accordingly, the switchingfunction is implemented with pulse transformers. In the figure,transistors and are seen to be coupled within line 744. Transistor isconfigured in conjunction with resistors 0 and 1 and capacitor 7.Correspondingly, complimentary transistor is implemented with resistors2 and 3 and capacitor 8. A capacitor 9 is coupled between lines 740 and742. Coupled to the gate of transistor is the secondary side of a pulsetransformer :B and similarly coupled to the gate of transistor is thesecondary side, :C of the same pulse transformer. A node is establishedbetween transistors and at line 746 which extends, in turn, to one endof the primary side of isolation transformer. Transformer was describedat bock 496 in connection with FIG. 34, and is represented in general bythat same number in the instant figure. The pulsed output at line 746 ismonitored for control purposes by a current transformer to providecontrol output signals CT- (line 963) and CT+ (line 962). Those signalsare employed in conjunction with the phase shift resonant controllerwhich controls inverter 490 (FIG. 46).

[0186] Transistor is configured in conjunction with resistors 4 and 5and capacitor 0. Similarly, transistor is configured with resistors 6and 7 and capacitor 1. Transistors and are connected in series withinline 748, and the node between them is tapped at lines 750-752 which arecoupled to another end of the primary side of isolation transformer.Complementary transistors and are switched by inputs into transformersecondary sides :B and :C respectively. Transistors - may be provided astype IR60 Repetitive Avalanche and d/v/dt Rated HEXFET® transistorsmarketed by International Rectifier, Inc. of El Segundo, Calif.

[0187] Now looking to the primary side controlling inputs to thesethree-winding transformers, the primary side, :A of the transformer isshown coupled through line 754 incorporating resistor 8, and line 756 tothe output terminals of a driver component 758. Device 758 may beprovided, for example, as a type MI424. Performing in conjunction with a+12V input and configured with capacitors 7-0 and resistors 9 and 0,connected with ground line 761, the device responds to inputs DRV_A andDRV_B derived from the drive circuit board as described earlier inconnection with arrow 616 and shown here being coupled to device 758 viarespective lines 759 and 760. Those inputs are derived by the controllerfor inverter 490 (FIG. 46).

[0188] The corresponding switching to transistors and is derived fromthe primary side of three-winding transformer at :A. That primary sideis coupled via line 762, incorporating resistor 7, and line 764 to theoutput terminals of a driver component 766 which also may be provided asa type MIC4424. Device 766 performs in conjunction with +12V and isconfigured with capacitors 1-3 and resistors 8 and 9 to respond tocontrol inputs DRV_C and DRV_D derived from the noted arrow 616 andprovided at respective lines 766 and 767 to carry out complimentaryswitching of the transistors and. Those inputs also are derived by thecontroller for inverter 490 (FIG. 46).

[0189] Looking momentarily to FIG. 43C, a schematic representation ofthe squarewave generated for example at, the switching node betweentransistors and is represented in general at 768. The correspondingsquarewave generated at the switching node intermediate transistors andis represented schematically at 770. When these squarewaves are inphase, there is no voltage difference between them and thus no voltageis impressed across the isolation transformer. However, the voltageoutput of the isolation transformer is controlled by modulating thephase between the squarewave arrays 768 and 770 to evolve a resultantsquarewave, for example, as symbolically represented at the right of theresultant wave 772.

[0190] Returning to FIG. 43A, as this inverter switching is carried out,the secondary side output of transformer is directed to each half of afull wave bridge rectifier described at block 500 in connection withFIG. 34. In what are referred to as “resonant transitions”, thecapacitors 0 and 1 as well as capacitors 7 and 8 combine with theleakage inductance of transformer to create soft switching resonanttransitions on the two switch nodes. Thus, transistor pairs and and andswitch in a very “soft” manner with low stress and with high efficiency.

[0191] The secondary side of isolation transformer is coupled via line774, incorporating relay contacts :B to line 776. Correspondingly, theopposite end of the secondary side of transformer is coupled via line778, incorporating relay contacts :B, to line 780. Relay contacts :B and:B are selectively actuated from the relay solenoids describedrespectively at :A and :A in FIG. 42. The relays correspond with block504 described in connection with FIG. 34. Line 776, incorporating diodes6 and 7 and line 780 incorporating diodes 8 and 9 comprise theearlier-described full wave rectifier 500 which is implemented incombination with resistors 0 and 1 and capacitors 4 and 5 to derive thed.c. link voltage across lines 782 and 784.

[0192] Filtering of the rectified d.c. link voltage further is providedby inductor and capacitor 6. Additionally, a resistor 2 is coupledbetween output lines 782 and 784 of this rectifying and filteringfunction. Capacitor 6 carries the D.C. link voltage monitored at line952 as a “LINK_V” signal which is used for a high gain controllerfeedback and other control purposes. Resistors 3 at line 784, 4 at line955 and 5 at line 954 are employed to derive the current-proportionalmonitor signals IFB− and IFB+ employed, inter alia, by the notedinverter 490 controller (FIG. 46).

[0193] The capability for amplitude modulation of the system RF outputmay be utilized at the commencement of any given electrosurgical cuttingprocedure carried out either by the pursing cables or by the precursorelectrodes to provide a “boost” in voltage for a short boost interval toaccommodate any cutting start or restart. Under such conditions, theelectrodes, whether precursors or pursing cables may be resting upontissue and encountering an impedance which may be too low to initiate anecessary cutting arc. In this regard, the cutting of tissue occurs whenhigh temperatures derived from an arc form a vapor between the cuttingelectrode and adjacent confronting tissue. Without evoking that arc atthe commencement of any cutting action, the electrode may be passingcurrent into the tissue to create a deleterious necrosing rather thandesired cutting activity. Accordingly, a modulation of the link voltageis provided for a three-eights second boost interval at start up with aboost amounting to the value of the square root of two times the normallink voltage. Thus, the electrodes may operate in either a normalcutting mode or a boost mode. Inasmuch as power is proportional to thesquare of the voltage, such an arrangement boosts the power by a factorof two during the boost interval. As noted above, this boost control aswell as the necessarily precise control over the link voltage is carriedout advantageously with the phase shifting control feature for thenetwork 490. In that regard, the LINK_V signal as at lines 782 and 952is fed back to the noted phase shift resonant controller (FIG. 46).

[0194] The link voltage which, as noted, is applied across capacitor 6,is applied to the RF inverter described earlier at block 510 inconnection with FIG. 34 and represented by the same general numerationin FIG. 43B. RF inverter 510 is configured as a resonant tank circuitcomprised of capacitors 7 and 8 along with an inductor. In this regard,note that the capacitors 7 and 8 are positioned within lines 786 and 788between lines 782 and 790. Similarly, inductor is coupled by lines 792and 794 between lines 782 and 790. To excite or induce oscillation inthe tank circuit, four MOSFET transistors -0 are selectively gated tocouple line 790 with D.C. link voltage line 784. The gate of transistoris configured with resistors 6 and 7 and line 796 which extends to oneoutput, OUTA, of a driver or buffer 798. The driver 798 is configuredwith capacitors 9 and 0, resistor 8 and +12V and responds to a DRV_RFsignal at its input line 800 to carry out gating. The device 798 may beprovided as a type MIC4424. The second output, OUTB, of device 798 iscoupled via line 802 with the gate of transistor. That coupling isconfigured in conjunction with resistors 9 and 0.

[0195] In similar fashion, the gate of transistor is configured withline 804 and resistors 1 and 2. Line 804 extends to the OUTA outputterminal of a driver or buffer 806. Driver 806 is configured withcapacitors 1-3, resistor 3 and +12V and receives a control input, DRV_RFat its input line 808. Device 806 also may be of the noted type MIC4424.The second output terminal, OUTB, of device 806 is coupled via line 810with the gate of transistor 0 which is configured in conjunction withresistors 4 and 5. A SYNC signal is generated from line 790 at line 812which is configured in conjunction with resistors 6-8 and capacitor 4.

[0196] The stable frequency sinewave generated by RF inverter 510 isapplied to the primary side of a step-up transformer described earlierat block 516 in FIG. 34 and identified generally by that same numerationin the instant figure. A stepped-up output from transformer is providedat lines 814 and 815. An inductor, at active electrode line 814 providesa smoothing of the sinewave output. The output at line 814 is directedthrough relay contacts :B and :B and coupling capacitor 5 to derive thecutting output, HV_PRECURSOR which is directed to the precursorelectrodes. Correspondingly, active electrode line 815, extending fromline 814, carries relay contacts :B and :B and extends in combinationwith coupling capacitor 6 to provide the electrosurgical cutting output,HV_CAPTURE which is supplied to the pursing cables 300-304. Relaycontacts :B-:B are controlled from the solenoid components describedabove in connection with FIG. 42 and function as components of outputstage 520 (FIG. 34). Return line 816 is coupled with the correspondingtwo pads or surfaces of the return electrode. In this regard, the lineis connected with coupling capacitor 7 and is coupled with PCSM circuit528 at line 1363 to provide an R signal. Line 816 is coupled to line 818and coupling capacitor 8 to provide a second return which is coupledwith PCSM circuit 528 at line 1362 to provide the signal R. A smallmonitoring current transformer is coupled with line 816 to develop thehigh voltage current monitoring signals HV_I− and HV_I+ at respectivelines 820 and 821.

[0197] Similarly, a voltage monitoring transformer 0 is connected withinline 822 between lines 814 and 816. The secondary of transistor 0 isconfigured in conjunction with rectifier-defining diodes 3-6, resistor 9and capacitor 9 to provide a voltage monitoring signal, HV_V at line824. A specially treated version of that signal provides an outer loopslow or low gain program input to the control of link inverter 490.

[0198]FIGS. 44A and 44B should be considered together in the mannerlabeled thereon. These figures are concerned with components mounted atthe drive board 622 (FIG. 36B) which carries, inter alia, monitoring andcontrol functions for the PFC boost converter 462 which has beendiscussed in connection with FIGS. 34 and 37B.

[0199] Looking initially to FIG. 44A, the pre-regulated 380 volt interimvoltage level as present at capacitors 2 and 3 and described inconnection with FIG. 37B in conjunction with lines 686 and 830 providesa monitoring input, +380V represented at line 830. The level of thisinterim voltage is divided by resistor grouping 0-2, filtered atcapacitor 0 and delivered via line 832 to one input of a comparator 834.The reference input to comparator 834 is derived from +5REF at line 836which incorporates level adjusting resistors 3 and 4 and provides thereference input at line 837. When the 380V input at line 830 is ofproper amplitude, comparator 834 provides an output at line 838incorporating resistor 5 which is submitted to an R-C timing networkrepresented generally at 840 and comprised of resistor 6 and capacitor 1within line 842. The time constant selected for network 840 accommodatesfor any line vagaries or the like. Accordingly, the slightly delayedsignal then is introduced via line 844 to one input of a buffer 846, theopposite input to which is provided from line 848. The output of buffer846 at line 850 extends to line 852 which is coupled through resistor 7to +12V primary power input at line 862. Line 852, is coupled via line858 to the gate of transistor 1. Transistor 1 is connected within line860, incorporating resistor 8, between line 862 carrying +12_PRI andprimary ground at line 864. Transistor 1 is turned off in response to alogic true low at line 850 to, in turn, energize the diode of anopto-isolator 866 via lines 868 and 870 from +12V primary power supply(+12V_PRI). The resultant output from the opto-isolator 866 provides alow logic true high voltage ok signal, HVOK, for enabling employment bycontroller circuitry at the lower voltage secondary side. See FIG. 46 inthe latter regard.

[0200] The 380V d.c. output itself is not enabled until assurance ismade that the A. C. input as described at line 450 in connection withFIG. 34, is at a proper level. The sensing of this value was providedfrom line 682 as described in connection with FIG. 37A. That AC_SENSE ismonitored as seen at line 872 which incorporates resistors 9 and 0 andcapacitor 2 and then is connected to line 864 and tapped at line 874. Aresistor 1 is incorporated between lines 874 and 864.

[0201] Looking to FIG. 44B, line 874 is seen to extend to one input of acomparator 876. The opposite input to comparator 876 is +5REF which isderived at line 878 intermediate resistor 2 and diode 0. The reference(+5REF) at line 878 is tapped at line 880 incorporating resistor 3 andcoupled through filtering capacitor 3 to line 864. Line 874, carryingthe adjusted AC_SENSE signal, extends to the opposite input ofcomparator 876, and in the presence of an appropriate voltage level, anoutput is provided by comparator 876 at line 882. Line 882 incorporatesresistor 4 and extends to line 884 wherein the output is subjected tothe time constant established by resistor 5 and capacitor 4. The outputfrom that R-C network then is directed via line 886 to one input of acomparator-buffer 888. The opposite input to buffer 888 is derived fromline 848 extending to line 890, in turn, incorporating resistors 6 and7. Filter capacitors are shown at 5 and 6 and the low logic true outputof comparator 888 at line 892 is seen to be directed to the gate oftransistor 2. Transistor 2 normally is held on from line 894incorporating resistor 8. The source of transistor 2 is connected withline 864 and its drain is coupled with line 896 incorporating resistor9. Line 896 is coupled, in turn, to line 898 which is filtered bycapacitor 7 and extends to the VREF terminal of the controller 900 forthe PFC boost converter 462. Note that line 896 further is coupled vialine 902 to the enabling input terminal EN/SYNC of device 900. Thustransistor 2 turns off in the presence of an AC_SENSE signal of properamplitude to enable controller 900 by application of a voltage from line898, resistor 9 and line 902. Device 900 may be provided as a typeLT1248 power factor controller marketed by Linear Technology Corp. ofMilpitas, Calif.

[0202] Line 892 additionally is seen to be coupled via line 904 andresistor 0 to line 862 which extends, in turn, to the source oftransistor 4. The gate of transistor 4 is coupled to line 904 by line906. Accordingly, the low true signal at line 892 functions additionallyto turn on transistor 4 providing a solenoid energizing true signal atline 908. In this regard, the signal at line 908 provides a RELAY_ILsignal which, in turn, functions to energize the relay solenoid :Adescribed in conjunction with FIG. 38. That relay closes the contacts :Bto shunt thermistor 670 (FIG. 37A) which had been active to avoidin-rush currents.

[0203] Controller 900 functions to derive the control input, DRV_PFCapplied to line 692 of driver device 686 described in connection withFIG. 37B. Line 692 is protected by diode 1. Device 900 performs inconjunction with a sensing of the 380V level output; the sensing of A.C. current, AC_I; and A. C. voltage, AC_V. 380V monitoring isrepresented at line 910 which incorporates resistors 1-3 and capacitor8. The adjusted voltage signal level then is introduced via line 912incorporating resistor 4 to the voltage sense terminal (VSENSE) ofcontroller 900. This signal level at line 912 also is extended via line914 to the CVP terminal of device 900. The A. C. current level signal,AC_I, is provided from line 916 and is derived from line 682 asdescribed in conjunction with FIG. 37B. This signal at line 916 is seento extend via line 918 and resistor 5 to the MOUT terminal of controller900. Line 916 also incorporates a resistor 6 and extends to line 920which, in turn, extends to the PKLIM terminal of controller 900. Line898 is seen to extend with resistor 7 to line 920. The A. C. voltagesignal, AC_V, is provided from line 922 and was derived at line 686 ofFIG. 37B. Line 922 is seen to incorporate resistors 8 and 9 and extendsto line 924 which, in turn, is coupled with the IAC terminal ofcontroller 900. Controller 900 performs in conjunction with the primarycircuit power supply, +12V_PRI as shown introduced from line 926incorporating diode 2. The device further is configured in conjunctionwith capacitors 2-1 and resistors 1-7.

[0204] As noted earlier herein the power factor correction developed inassociation with controller 900 not only permits the electrosurgicalgenerator to be used universally with diverse worldwide utility lineinputs, but also derives a pre-regulated interim voltage output whichpermits an optimization of the link inverter stage carrying out theconstant voltage-based control permitting generation of a sustainedcutting arc in the presence of an active electrode exhibiting a dynamicsurface area or geometry.

[0205] Looking to FIG. 45, the low voltage primary circuit powerfloating bias supply is depicted. The 380V d.c. level(FIG. 37B) istapped as represented at line 930 incorporating fuse and filtered bycapacitor 5. Line 930 extends to line 932 incorporating diodes 3 and 4and extending to the D (Drain) terminal of a regulator 934 which may beprovided as a type TO221P Three-terminal/Off-line PWM Switch marketed byPower Integration, Inc. of Sunnyvale, Calif. Component 934 is referredto as a 'smart power device”, combining a power transistor and a PWMcontrol circuit. Its source terminals are seen coupled to ground inconjunction with line 933. Line 932 is connected across the primary sideof a step down transformer T12 and asserts a chopped input thereto underthe control of device 934. The secondary side of transformer T12 isconnected at line 936 and diode D65 to line 938 incorporating rectifyingdiodes D66 and D67 and coupled via resistor R98 to the C (control) inputof device 934. This serves as a feedback to device 934. The primarycircuit power supply, +12V_PRI is then presented through resistor R99.Filtering capacitors are provided as represented at C86-C88.

[0206] Also located upon the drive board 622 is the resonant transitioncontrol integrated circuit which develops the DRV_A through DRV_Dcontrol signals which are submitted to the inverter 490 as described inconjunction with FIG. 43A. Referring to FIG. 46, this controller isshown at 950 extending from which the noted drive signals are identifiedin conjunction with respective lines 759, 760, 766 and 767 as arerepeated from FIG. 43A . The value of link voltage, LINK_V is submittedto the EAN and EAOUT terminals of device 950 from respective lines 952and 953 which are configured in combination with resistors R100-R102 andcapacitors C91 and C92. Line 952 reappears in conjunction withderivation of the LINK_V signal in FIG. 43A. This link voltage input atresistor R100 represents an inner relatively fast or high gain controlfeedback loop to the link voltage controller 950, which performs, interalia, in conjunction with an outer feedback loop program control whichis comparatively slow or of a low-gain nature. Link voltage currentrelated signals IFB- and IFB+are applied respectively from lines 954 and955 incorporating resistors R103 and R104 to the inputs of a type LP1215amplifier 958 which is configured in conjunction with resistors R105 andR106 and capacitor C93. The signals are derived with the noted lines inFIG. 43A. The output of amplifier 958 is provided via line 960 to the CSterminal of device 950.

[0207] Inverter 490 current signals, CT+ and CT−, are submitted viarespective lines 962 and 963 to rectifying diode pairs D70, D71 and D72,D73 configured within a network including capacitor C94 and resistorR107. Derivation of these signals is described in conjunction with FIG.43A. From this network, corresponding signals are submitted via line 964and resistor R108 to the RAMP terminal of device 950. Similarly, thesignal is submitted via resistor R109 to the ADS terminal and throughresistor R110 to line 960 and the CS terminal of device 950. The systemelected link voltage as well as its resultant control in deriving aconstant system output voltage is determined by a signal identified as“VPROG” (FIG. 47A) which is submitted via line 968 to the EAP terminalof device 950. Line 968 is configured in conjunction with resistor R111and capacitor C95 and is coupled through pull-up resistor R112 to 5VREF, the latter reference having been described in conjunction withFIG. 44B. As noted above, an outer feedback control loop, ultimatelyresponsive to the level of system output voltage is combined with a highgain inner loop. This arrangement permits a constant voltage-basedcontrol accommodating the otherwise unstable oscillative tendenciesposed by the negative dynamic impedance of the required cutting arc, aswell as the impedance variation exhibited by the cables when operatingin a capture mode. Accordingly the outer feedback loop signal, VPROGapplied at line 968 is programmed to device 950 in a very slow manner byselecting a relatively high capacitance value for capacitor C95, forexample, 4.7 micro-farads, evolving a time constant of about 35milliseconds. This achieves a stable, constant voltage control over theRF inverter 510 output.

[0208] Device 950 also is selectively enabled or disabled in response tothree signal inputs. One of those signal inputs is the earlier-describedlogic low true HVOK signal generated from interim voltage responsiveopto-isolator 866 described in conjunction with FIG. 44A. This activelow signal, HVOK, is seen introduced via line 970 which is coupled to+12V through pull-up resistor R113. Line 970 extends through steeringdiode D74 and lines 972 and 974 to the gate of a MOSFET transistor Q13.Line 974 is coupled through resistor R114 to ground and transistor Q13is seen coupled between ground and lines 976 and 978 to the softstart/disable terminal of device 950. Line 976 extends to ground throughcapacitor C96. Accordingly, when the signal at line 970 is at a logichigh value, representing an inadequate interim voltage level, thentransistor Q13 is turned on to bring line 978 to a logic low condition.This disables device 950 until such time as a logic true low conditionoccurs at line 970, whereupon transistor Q13 turns off to remove the lowsignal at line 978 and permit the internal circuitry of device 950 toeffect its enablement.

[0209] As the practitioner actuates the energize/position switch 55 oninstrument 12 or the footswitch 86 a, a high voltage output is calledfor to energize the precursor electrodes. Before that condition occurs,the d. c. link voltage must be created. The PLD based control system(FIG. 62A, line 1237) thus provides a logic high true DC_LINK_ENABLEinput as shown at line 980 incorporating resistor R115 and configured inconjunction with filter resistor R116 and filter capacitor C97. Line 980extends to an inverter buffer 982 having an output at line 984 extendingthrough steering diode D75 to line 972. Thus lines 984, 972 and 974 aremaintained at a logic high level to turn on transistor Q13 and effectdisablement of device 950 until line 980 assumes a high logic level uponenabling command, DC_LINK_ENABLE from the PLD-based control. Accordinglyin the absence of an appropriate link enable signal, or an HVOK signal,device 950 will not provide a link control. Device 982 may be providedas a type CD40106B CMOS Schmitt trigger marketed by Texas Instruments,Inc. of Dallas, Tex. Use of such a component takes advantage of itsfiltering histeresis characteristic.

[0210] A detected d.c. link over-voltage fault condition will derive alogic high true “DISABLE” signal (see FIG. 59) which is presented atline 974 through steering diode D76. Accordingly, if such a fault arisesin the absence of a BOOST_MASK signal (FIG. 47A), the system will beshut down. It is at this location through diode D76 that such shut downactivity takes place by turning on transistor Q6. Device 950 is seen tobe further configured in conjunction with capacitors C98-C102 andresistors R117-R121 and may be provided as a type UCC3895 BiCMOSAdvanced Phase Shift PWM Controller marketed by Unitrode Corp. ofMerrimack, N.H.

[0211] Referring to FIG. 47A, the control system output voltage outerloop monitoring circuit feature carried at the drive board isillustrated. The high voltage output monitoring signal described in FIG.43B as HV_V at line 824 is filtered as described in conjunction withFIG. 56 to provide the signal, VOUT which is introduced to line 1002.Line 1002 incorporates input resistor R125 and extends to one input ofan error amplifier 1004. The reference input to device 1004 is derivedfrom a potentiometer represented generally at 1006 incorporating aresistor component R126 and a capacitor C107. Resistor component R126 iscoupled with a 7.5V reference input.

[0212] Looking momentarily to FIG. 47B, the derivation of that referenceis illustrated. In the figure, line 1008 incorporating resistor R127 anddiode D78 is tapped to provide the 7.5REF signal at line 1010 whichreappears in FIG. 47A. A wiper arm extended input to device 1004 isrepresented at line 1012. The output of comparator 1004 at line 1016represents an output voltage error signal which is directed to lines1018, 1019 and input resistor R128 to the IN1, V-, GND, and IN4terminals of an analog switching device 1020. Analog switch 1020 isprovided as a type MAX4665 CMOS analog switch, marketed by MaximIntegrated Products of Sunnyvale, Calif. Line 1018 extends from inputline 1002 to the COM2 terminal of analog switch 1020 and incorporatesresistor R199 along with blocking diode D79. This arrangement assures aunidirectional input to device 1020. Switch 1020 additionally respondsto a logic high true “BOOST_MODE” signal generated from the controlboard PLD (FIG. 61, line 1240) and shown presented at line 1022. It maybe recalled that the boost mode provides for increasing the outputvoltage and thus the power output of the precursor electrode and thepursing cables for about three-eighths second at any start-up orrestart. Line 1022 is configured in conjunction with resistors R129 andR130 and capacitor C108 and extends to the input of a buffer inverter1024. Device 1024 may be provided as a type CD40106B Schmitt trigger(supra). Accordingly, the logic high true signal at line 1022 isinverted to a logic low at line 1026 and is directed via lines 1028 and1029 to the IN2 and IN3 terminals of device 1020 to create a boost modeof performance.

[0213] Because the control system includes a d.c. link over-voltagefault condition, it is necessary to simultaneously develop a“BOOST_MASK” signal to overcome a false fault condition during a boostmode. Accordingly, line 1026 is seen to incorporate a steering diode D80which is positioned forwardly of an RC network shown generally at 1030and comprised of resistor R131 and capacitor C109 extending between +12Vand secondary ground. Network 1030 provides a normally high input to acomparator 1031 to establish a normally logic low at its output line1157. The opposite input to device 1031 at line 1032 carries the 7.5REFsignal described in connection with FIG. 47B. Comparator 1031 provides alogic or active high BOOST_MASK output at line 1157 upon the occurrenceof a boost mode indicating logic low at line 1026. The BOOST_MASK activehigh output at line 1157 is present during the occurrence of theBOOST_MODE command. As a safety feature, however, following thetermination of the BOOST_MODE command signal, the logic high BOOST_MASTcondition at line 1157 will persist for about the time constant of RCnetwork 1030. In this regard, upon the assumption of an active lowcondition at line 1026, capacitor C109 immediately discharges. At thetermination of the boost mode, diode D80 is back-biased and capacitorC109 is gradually charged through resistor R131 to ultimately establisha voltage level causing boost mask comparator 1031 to revert its outputto a logic low level removing the BOOST_MASK signal.

[0214] Device 1020 responds to the condition at lines 1028 and 1029 toprovide a boost voltage value signal level through resistor R132 whichderives the VPROG signal for a boost mode output at line 1034. In theboost mode, power is increased by a factor of two. Accordingly the linkvoltage may be increased by VPROG by the square root of two, power beingproportional to the square of voltage. In general, the boost voltagelevel will be greater than the normal cutting voltage level by a factorwithin a range from about 1.2 to about 1.5. Alternately, the device 1020provides a lower level, normal cut voltage value signal at line 1034 asis established by the resistance value of a resistor R133. Thoseresistors R132 and R133, in effect, form a voltage divider with pull-upresistor R112 described in FIG. 46. To assure a unidirectional input todevice 1020, line 1018 is coupled to the COM2 terminal of switch 1020and serves as a feedback line incorporating blocking diode D80 extendingthrough resistor R149 to line 1000. Device 1020 further is configuredwith +12V source and a capacitor C110 at line 1038 and may be providedas a type MAX4465, 5-ohm, SPST, CMOS Analog Switched marketed by MaximIntegrated Products of Sunnyvale, Calif.

[0215] Referring to FIG. 47C a control system power derivation circuitfeature carried by the drive board as illustrated. Overall power isdetermined by a monitoring of the output voltage and output current toderive signals VOUT and IOUT for presentation a respective lines 990 and991 extending to a solid state multiplier 992. The derivation of thesignals is described in conjunction with respective FIGS. 56 and 55.Device 992 may be provided, for example, as a type AB633JN AnalogMultiplier marketed by Analog Devices, Inc., of Norwood, Mass.Multiplier 992 is configured in conjunction with +12V and −10V powersupply inputs, as well as capacitors C104 and C105. Forming a componentof a power derivation network, the product output of multiplier 992 atline 994 is sent to an integrating resistor R122. Line 994 furtherextends to lines 996 and 998, the latter line incorporating anintegrating capacitor C106. Line 996 further extends to a diode D77 andto the input of an amplifier 998. With the arrangement shown, power is,in effect, computed in accordance with the conventional expression:$P = {\frac{1}{T}{\int{{vi}{t}}}}$

[0216] Thus, capacitor C106 carries a monitored power signalproportional to output power. That signal is fed to amplifier stage 998which is configured with resistors R123 and R124 to double the amplitudeof the signal. This provides a power value signal utilized by the systemat line 1000 identified as “PWR_OUT” to monitor for an excessive outputpower condition. (See FIG. 57).

[0217] Referring to FIG. 48, the circuitry providing the control input,DRV_RF applied to devices 798 and 806 in FIG. 43B for the RF resonantinverter 510 is illustrated. In the figure, the basic frequency isderived with an oscillator integrated circuit 1040 which may be providedas a type LMC555 CMOS Timer marketed by National Semiconductor Corp. ofSanta Clara, Calif., which is configured in conjunction with capacitorsC111-C113 and resistors R134 and R145. Frequency adjustment may beprovided by the manufacturer in conjunction with a potentiometerrepresented at 1042. The frequency output of device 1040 is presentedalong line 1044 to the trigger input of another type LMC555 device 1046which establishes pulse width. Device 1046 is configured in conjunctionwith capacitors C114-C116 and resistor R136. Pulse width is adjusted bythe manufacturer at a potentiometer represented at 1048. Devices 1040and 1046 are simultaneously enabled both by PLD and start-up resetderived ENABLE inputs respectively provided at lines 1050 and 1052. Inthis regard, while enablement is provided on the occasion of asequential signal ultimately provided from the PLD, the RF inverter isnot permitted to be enabled during initial system startup. Accordingly,as a safety feature, the logic or active high ENABLE signal is notprovided until after the interval of Power-On Reset (PWR_ON_RST, FIG.54). The final control signal, DRV_RF is provided from device 1046 atline 1054 which incorporates a resistor R137.

[0218]FIGS. 49 through 53 illustrate circuitry associated with the logicused in conjunction with the energization of the motor 170 a of motorassembly 170. In this regard, motor current, identified as “MOTOR_I” ismonitored to carry out this logic. That monitored current is generallytoo low to be useful and its derivation is described in connection withFIG. 42. Thus, it is amplified initially to develop an enhanced signalidentified as “MOTOR_CURR”. FIG. 49 shows the amplification of thesesignals. In this regard, the initial current signal is introducedthrough resistor R137 and line 1060 to an amplifier 1062. Amplifier 1062is configured in conjunction with resistors R138-R140 and capacitorsC117 and C118 and provides an enhanced MOTOR_CURR signal at output line1064.

[0219]FIGS. 50 through 53 provide varying threshold analyses of themotor current for use by the PLD logic device of the system. FIG. 50shows the initial threshold test which is to determine, at the outset ofmotor energization, whether the motor is indeed working. For thispurpose, a small amount of free movement of the yoke 184 is permittedprior to contact being made with the ears as at 134 and 136 (FIG. 6) ofthe drive member 324. During this very short test interval (about 0.5second), the motor current is very low but discernable, for example,exhibiting at least about a 10 milliamp threshold value. If the motor isnot on at a time when it should be on, then a system fault will be athand with appropriate shut-down and visual cueing. FIG. 50 shows thatthe MOTOR_CURR signal is introduced at line 1066 to one input of acomparator 1068. The reference input to comparator 1068 is the earlierdescribed 7.5REF disclosed in connection with FIG. 47B. That referencevoltage is adjusted by resistors R141-R143 and introduced via line 1070to device 1068. The output of device 1068 is provided at line 1072 whichis coupled to +12V source through a pull-up resistor R144. Where theproperly performing motor current level has been detected, a “MOTOR_ON”signal is generated by turning off transistor Q16.

[0220] Looking to FIG. 51, the MOTOR_CURR signal is introduced tocomparator 1074 from along line 1076. Comparator 1074 is configured withthe 7.5REF reference signal and resistors R145-R147 to react to athreshold provided at line 1075 representing, for instance, about 23milliamps of motor current draw. As the yoke 184 engages the ears 134and 136 (FIG. 6) the motor will commence doing more involved work andtypically will exhibit a current draw of about 45 milliamps. Thiscondition then is witnessed at comparator 1074 and where the establishedthreshold for this motor condition is exceeded, then comparator 1074reacts at its output line 1078 to turn off transistor Q17. Thus, a“MOTOR_ENGAGED” signal is generated for the logic of the control system.As before, line 1078 is coupled with +12V through pull-up resistor R148.The networks of FIGS. 50 and 51 perform in concert. A determination bythe network of FIG. 50 during the initial 0.5 second test interval thatmotor current is above a low threshold, for example, of 5 milliamps,results in the MOTOR_ON signal being generated. However, during thissame test interval, should the motor current exceed the threshold of thenetwork of FIG. 51 to result in a MOTOR_ENGAGED signal, then thisinitial test fails, resulting in a fault condition. (See FIG. 70D, block1560). Following passage of the initial one-half second test, thenetwork of FIG. 51 will detect whether or not its threshold, forexample, of 23 milliamps has been met. That indicates appropriateengagement of the yoke 184 with ears 134 and 136. If during forwardmovement of drive member 324, the threshold of the network of FIG. 51 isnot sustained, a fault condition results with a system halt and visualcueing.

[0221] Referring to FIG. 52, as a tissue capture is completed, forexample, as illustrated in connection with FIG. 29, the motor will entera forward stall condition and the current will rapidly spike to about130 milliamps. Looking to FIG. 52, the MOTOR_CURR signal again isintroduced to a comparator 1080 via line 1082. Comparator 1080 isconfigured with 7.5REF and resistors R149-R151 to react to a thresholdat line 1083 to, in turn, provide an output at output line 1084 whenforward stall current levels are present. As before, line 1084 iscoupled through pull-up resistor R152 to +12V source and is coupled tothe gate of transistor Q18. Accordingly, a “MOTOR_STALL” signal isgenerated by the turning off of transistor Q18.

[0222] Upon detecting the forward motor stall, the logic of the systemreverses the drive polarity to the motor 170 a and the transfer assembly180 releases from its abutting engagement with drive member 324, ears134 and 136, whereupon it is driven back to its “home” position asdescribed in connection with FIG. 5. (See FIG. 42). The resultantreverse stall current is of lower amplitude than the forward stallcurrent and is detected. Looking to FIG. 53, the MOTOR_CURR signal isintroduced at line 1086 to a comparator 1088. The reference level forcomparator 1088 is set for the detection of a reverse stall currentlevel and is provided at line 1089, from 7.5REF in conjunction withresistors R153-R155. Upon detection of a reverse stall condition, outputline 1090, which is coupled to transfer Q19 as well as through pull-upresistor R156 to +12V source, assumes a logic low level and transistorQ19 is turned off to establish a “MOTOR_REV_STALL” condition or signal.Comparators 1068, 1074, 1080 and 1088 may be provided, for example, astype LM339 Low Power, Low Offset Voltage Comparators, marketed byNational Semiconductor Corp. (Supra).

[0223] Looking to FIG. 54, circuitry is represented which provides“ENABLE” and “RESET” signals upon the occurrence of respectiveRF_INV_ENABLE and PWR_ON_RST signals. The latter reset signal isdeveloped from the control system PLD. (See FIG. 61A). In the figure,the former logic high true input signal is introduced through resistorR157 at line 1092 to the input of a Schmitt trigger implemented buffer1094, the logic low inverted output of which at line 1096 extendsthrough ORing diode D82 to the input of a second inverter 1098 toprovide an active or logic high “ENABLE” signal at output line 1100.Filtering resistor R158 and filtering capacitor C119 are coupled to line1092, and the hysteresis characteristic of device 1094 also providesfiltering. The logic or active low power on reset (PWR_ON_RST) signal isintroduced through resistor R159 and line 1102 to the input of a Schmitttrigger implemented buffer 1104, the logic low output of which isprovided at line 1106 which is directed to the input of an inverter1108. The logic high output of buffer 1108 provides a “RESET′ signal atline 1110 and also negates the ENABLE signal at line 1100 by a wiredORing established via line 1111, ORing diode D83 and line 1112. Line1112 is coupled through resistor R160 to ground. Filtering resistor R161and filtering capacitor C120 are coupled between line 1102 and ground.As noted earlier, as a safety feature, the RF inverter operation isblocked during system startup occurring during the power on resetinterval. This is achieved, inter alia, by the above-noted ORingarrangement derived with diodes D82 and D83, which functions to removethe ENABLE signal during this initial interval. Devices 1094, 1098,1104and 1108 may be provided as type CD40106B CMOS Schmitt triggers (Supra).

[0224] Referring to FIG. 55, comparator circuitry monitoring for a highvoltage over-current condition is revealed. In the figure, the currentsignals HV_I+ and HV_I− as were developed at the high voltage outputstage 520 as described in connection with FIG. 43B are rectified. Inthis regard, positive current is introduced to intermediate diode pairD84 and D85 from line 821 and the negative current signals areintroduced to diode pair D86 and D87 from line 820. These rectifyingdiode pairs are located between lines 1114 and 1116. The signal “IOUT”is developed from line 1114 and is represented at line 991 (See FIG.47C). Capacitor C121 and resistor R162 provide a filtering function,while diode D88 functions as a clamp. Line 1114 extends to one input ofa comparator 1116 having an output at line 1118 coupled through pull-upresistor R163 to +12V source. Comparator 1116 is configured forestablishing a high voltage over-current threshold reference input atline 1120 in conjunction with +12V source and resistors R164-R166.Output line 1118 extends via line 1122 to the gate of transistor Q20.Accordingly, a low true output at the comparator 1116 generates acorresponding over-current condition, “HV_OC” at line 1245 by turningoff transistor Q20. (See FIG. 61A where that line reappears).

[0225] Looking to FIG. 56, comparator circuitry is illustrated whichdetermines the presence of an over-voltage condition at the generatoroutput. The HV_V signal, the derivation of which was described inconnection with FIG. 43B, line 824, is introduced to line 1124 andresistor R167 to be asserted at one input of a comparator 1126. Line1124 is coupled with a filter capacitor C122 and clamping diode D89. Theover-voltage reference input to device 1126 is provided at line 1127 andis derived from +12V source in conjunction with resistors R168-R170 andthe low true logic output of device 1126 is provided at line 1128 whichis coupled through pull-up resistor R171 to +12V source. Output line1128 is connected through line 1130 to the gate of transistor Q21.Accordingly, a low true output at comparator 1126 turns off transistorQ21 to create an over-voltage condition “HV_OV” at line 1244 whichreappears in FIG. 61A. Devices 1116 and 1126 may be provided as typeLM339 comparators (supra).

[0226] Referring to FIG. 57, a comparator circuit is illustrated whichdetermines the presence of an over-power condition at the generatoroutput. This monitoring is carried out in conjunction with the PVWR_OUTsignal, the derivation of which was described in connection with FIG.47C. That signal is introduced through resistor R172 and line 1132 toone input of a comparator 1134. A reference input to comparator 1134 isderived in conjunction with a potentiometer network incorporatingresistors R173 and R174, capacitor C128 and the reference, 7.5 REF, thederivation of which was described in connection with FIG. 47B. Theoutput of device 1134 at line 1136 is coupled through pull-up resistorR175 to +12V source and to the gate of transistor Q22. Accordingly, alow true output of device 1134 turns off transistor Q22 to derive an“OVER_POWER” condition at line 1256 which reappears in FIG. 61A. Afilter resistor R176 is connected between line 1132 and ground.Comparators 1116 and 1126 may be provided as type LM339 devices, whilecomparator 1134 may be provided as a type LT1215 device.

[0227] Referring to FIG. 58, an over-temperature circuit is portrayed.The temperature signal, TEMP having a low true condition when monitoredtemperature is excessive, has been described in connection with FIG. 39.Line 697 from the temperature responsive device, described in thatfigure, incorporating a resistor R177, is coupled through pull-upresistor R178 to +12V source and extends to the gate of transistor Q23.A filter capacitor C123 is coupled between lines 697 and ground. Withthe arrangement shown, a low true “OVER_TEMP” signal is derived at line1254 which reappears in FIG. 61A in the presence of an excessivehardware temperature.

[0228] The d. c. link voltage has been described in connection with FIG.43A as being monitored at line 952. That monitoring signal has beenidentified as “LINK_V”. The control system determines whether thisvoltage is either above or below a window of acceptable operation. Ofcourse, such a window may reduce to a point value.

[0229] Referring to FIG. 59, the LINK_V input is seen introduced withline 952 and resistor 178 to one input of a link over-voltage comparator1136. A filter resistor R179 is connected between line 952 and ground.Additionally connected to line 952 is line 1138 which extends to theinput of a link under-voltage comparator 1140. The reference inputs forboth comparators 1136 and 1140 are derived from +12V source at line1142. In this regard, +12V source is introduced to line 1142 throughresistor R180 and that reference value then is directed to device 1136through line 1144. Line 1142 additionally incorporates resistors R181and R182 to establish a d. c. link under-voltage threshold referenceinput to comparator 1140 at line 1146. Line 1142 is filtered by acapacitor C124.

[0230] The output of comparator 1136 at line 1148 is coupled throughpull-up resistor R183 to +12V source; is coupled with filter capacitorC124; and extends to the S (set) terminal of an RS flip-flop 1150configured latch. Device 1150 may be provided as a type 4013B CMOS Dual“D” type Flip-Flop marketed by Texas Instruments, Inc. of Dallas, Tex.If the level of monitored link voltage at line 952 exceeds the thresholdestablished at line 1144, output line 1148 assumes a logic highcondition to cause latch 1150 to assume a set state. As a consequence,its Q output at line 1152 changes to a logic high level to create theDISABLE signal turning on MOSFET transistor Q13 (FIG. 46) to disable thelink voltage controller 950. A complimentary low true output occurs atthe Q -terminal at line 1154. Line 1154 is coupled to the gate of MOSFETtransistor Q24, the drain and source terminals of which are coupledrespectively with line 1198 and ground. This turns off transistor Q24 toderive the link over-voltage signal, “DC_LINK_OV”, which is transmittedto and further developed at the control PLD.

[0231] As discussed in connection with FIG. 47A, during an enhanced linkvoltage-based boost mode, a logic high true BOOST_MASK signal isdeveloped at line 1157. Line 1157 reappears in the instant figureextending through ORing diode D92 to line 1156 incorporating resistorR184 and extending to the reset (R) terminal of latch 1150. Accordingly,during the boost mode, latch 1150 is held in a reset state wherein its Qterminal at line 1152 is held at a logic low to block any DISABLE signaland its Q terminal at line 1154 is held at a logic high level turning ontransistor Q24. Thus the DC_LINK_OV signal is blocked for the durationof the boost mode.

[0232] As another feature, during the interval of power-up reset, thesystem holds latch 1150 in a reset state to assure theover-voltage-based signals as above discussed will not appear at lines1152 and 1154. Accordingly, the active high level RESET signal developedas described in connection with FIG. 54 at line 1159 is transmittedthrough ORing diode D91 to line 1156 and the reset terminal, R of latch1150. It may be recalled from FIG. 54 that the presence of a RESETsignal negates an ENABLE signal to disable the RF inverter 490 function.Line 1156 is seen to extend from the reset, R terminal through resistorR184 to ground.

[0233] Looking to d.c. link under-voltage comparator 1140, the output ofthis device is provided at line 1158. Line 1158 is coupled with pull-upresistor R185 to +12V source and through resistor R186 to input line1138. Output line 1158 extends to the gate of MOSFET transistor Q25.Accordingly, in the presence of an under-voltage at the d. c. link, thenthe output of comparator 1140 at line 1150 assumes a low logic truecondition to turn transistor Q25 off and a d. c. link under-voltagesignal, “DC_LINK_UV” is generated for conveyance to the PLD at thecontrol board. Device 1136 and 1140 may be provided as type LM339comparators (Supra).

[0234] Referring to FIG. 60, a power converter and isolation circuitemploying a network for response to actuation of the footswitch 86 andvacuum switch 51 (FIG. 1) is portrayed. This circuit is designed toaccommodate footswitch and vacuum switch devices which do not havebuilt-in electrical isolation characteristics. Thus, an opto-isolatorfeature is provided. In the figure, +12V source is applied throughresistor R187 and line 1160 to the primary side, T13:A of an isolationtransformer T13. Line 1160 is filtered with capacitors C125 and C126.The opposite side of transformer primary T13:A at line 1162 is coupledwith the drain terminal of transistor Q26. A blocking diode D93 extendsacross the drain and source terminals of transistor Q26. The gate oftransistor Q26 is coupled by line 1164 to the OUT terminal of powerconverter 1166. Line 1164 is coupled with filter resistor R188 andclamping diode D94. Provided, for example, as a type UC3845 devicemarketed by Unitrode Corp. of Merrimack, N.H., converter 1166 isconfigured with resistor R189 and capacitors C127 and C128 and functionsto chop the input to primary transformer side T13:A by selectivelyturning transistor Q26 on and off. One secondary of transformer T13shown at T13:B derives a −10V output and is shown performing inconjunction with rectifying diode D95, resistor R190 and filtercapacitor C153. The −10V source is employed with multiplier 992 (FIG.47C) at line 993.

[0235] A next secondary side of transformer T13 is shown at T13:C,providing for electrical isolation of footswitch 86 and vacuum switch51. The input lead pair from each of the footswitches 86 a-86 c as wellas the vacuum switch 51 are opto-isolated and connected with secondaryside T13:C. One side of secondary T13:C is coupled at line 1168incorporating rectifying diode D96 and resistor R191. The opposite sideof secondary T13:C is coupled to line 1172. Capacitor C129 and resistorR193 extend between lines 1168 and 1172 and, in effect, a node utilizedby four identical isolation networks is developed across resistor R193.The first of these networks, for example, associated with footswitch 86a incorporates line 1168 and resistor R192 which extends to the anodeinput of opto-isolator 1170. The cathode input of opto-isolator 1170 iscoupled with line 1174 which extends to one side of footswitch 86 a andis labeled “FOOTSWITCH_1A”. Line 1172 extends to the opposite side ofswitch 86 a and is labeled “FOOTSWITCH_1B”. The low voltage output sideof opto-isolator 1170 is connected at line 1176 to the gate oftransistor Q27 and the opposite output thereof is coupled via line 1178to its source terminal and to secondary circuit ground. Line 1176 iscoupled through pull-up resistor R192 to +12V source and, accordingly,with the actuation of footswitch 86 a, the signal “FOOTSWITCH_1 ” isproduced in low logic true fashion at line 1180. This network,incorporating resistors R192 and R194 opto-isolator 1170, and transistorQ27 is repeated and connected across resistor R193 for the remainingfootswitches 86 b and 86 c as well as for vacuum switch 51. Accordingly,the same network identifying numberation is used to describe thesenetworks, but in primed fashion. In this regard, the footswitch 86 bnetwork is identified in single primed fashion in combination with theswitch labels “FOOTSWITCH_2A” and “FOOTSWITCH_2B” providing the lowlogic true output signal “FOOTSWITCH_2”. Footswitch 86 c is identifiedin double primed fashion in combination with the switch labelsFOOTSWITCH_3”. Similarly the vacuum switch 51 network is identified intriple primed fashion in combination with the switch labels“VACSWITCH_A” and “VACSWITCH_B”, providing the low logic true outputsignal, “VACSWITCH”.

[0236] As described in connection with FIG. 36A, the control boardcomponent 624 of the controller is characterized principally in theincorporation of a programmable logic device (PLD) which generally is ahardware programmable compilation of logic gates. This gate compilationresponds in a sequential logic to develop a series of states effecting acontrol for the system at hand. This device, may be, for example, a typeEPM7192SQC160-15 Programmable Logic Device marketed by Altera, Inc. ofSan Jose, Calif. The device is represented at 1190 in FIG. 61A. Board624 also incorporates filtering and logic-supporting pull-up functions.In general, where transistors have been described as being turned off,the relevant lines typically are pulled to a logic high at the controlboard. FIG. 61A should be considered in conjunction with FIGS. 61B-61Ein the manner labeled thereon to reveal those connections of featuresdrawn so as to connect in uninterrupted fashion with this logic center.In FIG. 61A, a regulated +5V and associated ground are shown introducedfrom respective line arrays 1192 and 1194 to corresponding terminals ofdevice 1190. The +5V inputs are shown filtered by a six capacitor array1196.

[0237] Looking additionally to FIG. 61 B, a clock network is representedgenerally at 1198. Network 1198 includes a crystal oscillator device1200 which may be provided, for example, as a type 74302 marketed byM-Tron Industries of Yankton, S.D., which responds to an_RESET inputapplied at line 1202. Configured in conjunction with inductor L10 andcapacitors C130-C132, the network 1198 provides a 1 KHz input at line1204 to PLD 1190.

[0238] Looking to FIG. 61C, a reset network is shown generally at 1206which functions to hold the system low for a specified amount of time toassure a power supply stabilization. It may be recalled that, duringthis reset interval, as a safety feature, the RF inverter 490 functionis not enabled (FIG. 5A). Network 1206 performs at the time of systempower on or at such time as the regulated 5V power supply for theinstant circuit diminishes to a certain extent. The network is centeredabout reset device 1208 which may, for example, be a type DS1233DZ-5marketed by Dallas Semiconductor, Inc. of Dallas, Tex., and which isconfigured in conjunction with capacitors C133 and C134 as well asresistor R201. A_RESET output is provided at line 1202 which isdescribed in connection with FIG. 61 B as being introduced to oscillatordevice 1200. The same signal is directed via line 1210 to the _RESETterminal of PLD 1190. PLD 1190 also provides the logic high truePWR_ON_RST signal at line 1212 as described in conjunction with FIG. 54.

[0239] Returning to FIG. 61A, an externally accessible jumper orconnector is shown at 1214 which provides a four line array input to I/Oports of PLD 1190 as shown in general at 1218. Three of those four linesof the array 1218 are pulled up to +5V through a pull-up resistor arrayshown generally at 1220.

[0240] Extending from PLD 1190 is a four line array shown generally at1222 which provides an output for controlling four relays of the PCSMcircuit 528 (FIG. 34). Below array 1222 is a line 1224 providing a PCSMcircuit enablement signal, PCSM_ENBL. Below line 1224 is an input line1226 carrying a PCSM circuit valid input signal, PCSM_VALID. The PCSMcircuit is discussed in detail in connection with FIGS. 66A-66C and68A-68B.

[0241] Looking momentarily to FIG. 61D, the four line array 1222reappears extending to input terminals of a buffer circuit 1228.Additionally extending to the input of device 1228 is an LED activationsignal from PLD 1190 identified as “LED_DRVIN” and provided at line1230. The corresponding buffered outputs are shown at five line array1232, the upper four lines of which are directed to relays of the PCSMcircuit and the fifth of which provides the signal “_LED_DRVOUT”.

[0242] Returning to FIG. 61A, the d. c. link monitoring features asdescribed in conjunction with FIG. 59 as being inputted to PLD 1190 areshown at input lines 1234 and 1235. Corresponding link relay 504activation (FIG. 42) link enablement (FIG. 46) are provided at outputlines 1236 and 1237. Below that grouping is an array 1239 of input andoutput lines to PLD 1190 concerned with the high voltage output functionincluding the boost mode signal, BOOST_MODE, at line 1240, earlierdescribed at line 1022 (FIG. 47A), the high voltage precursor electrodecut signal, RELAY_CUT (FIG. 42) as represented at line 1241, the highvoltage capture cutting signal, RELAY_CAPTURE (FIG. 42) represented atline 1242, the RF inverter 510 enablement signal, RF_INV_EN at line1243, introduced at line 1092 in FIG. 54, the high voltage over-voltageinput HV_OV (FIG. 56) at line 1244 and the high voltage over-currentinput HV_OC (FIG. 55) represented at line 1245.

[0243] Below line array 1239 is another array 1247 of inputs and outputsto PLD 1190. At this array 1247, input lines 1248 and 1249 are concernedrespectively with motor forward (MOTOR_STALL) and reverse(MTR_REV_STALL) stall. Output lines 1250 and 1251 are concerned withmotor forward (RELAY_FWD) and motor reverse (RELAY_REV) drives. Input atlines 1252 and 1253 respectively carry the signal; MOTOR_ON, monitoringinitial motor energization with turning and a monitoring condition,MTR_ENGAGED, active when the yoke 184 has engaged the drive member 324.These motor functions as identified in connection with lines 1248, 1249,1252 and 1253 have been discussed in connection with FIGS. 50-53, whilelines 1250 and 1251 reappear in FIG. 42.

[0244] The over-temperature, OVER_TEMP (FIG. 58) input to PLD 1190 isshown at line 1254; while a low voltage power supply under-voltagecondition, signal, LVRS-UN (FIG. 63) is inputted at line 1255 and theover-power condition signal, OVER_POWER as described in connection withFIG. 57 is inputted to PLD 1190 as represented at line 1256.

[0245] Looking to the opposite side of PLD 1190, a thirteen line arrayis represented generally at 1258. Of the lines within array 1258,certain of them carry signals responding to external switching and aninterlock test, as well as providing outputs for selectivelyilluminating light emitting diodes (LEDs) both at the front panel ofconsole 64 and at the instrument 12 housing 14.

[0246] Above the line array 1258 a line array 1264 is shown withlabeling corresponding with the opto-isolated input signals fromfootswitches 86 and vacuum switch 51. These input signals were discussedabove in connection with FIG. 60.

[0247] Referring additionally to FIG. 61E, line array 1258 reappears andthe inputs and outputs represented thereby may be seen to extend throughintermediate signal treatment features to three connectors 1260-1262.Connector 1260 is coupled with a printed circuit board 642 (FIG. 36A)located at the upper portion of the front panel of console 64; connector1261 is coupled with a lower panel assembly serving the lower portion ofthe front panel of console 64; and connector 1262 is operationallyassociated with connector 66 (FIG. 1) performing in conjunction with thehousing assembly 14 of instrument 12.

[0248] Line 1265 which carries a start switch signal identified as“START_SW” as initially derived by the actuation of switch 92 on console64 (FIG. 1) is uppermost in array 1258. This is the only console-mountedswitch having an input to PLD 1190. The switch must be actuated in orderfor any procedure to commence, the switch signal being utilized for aninitial setup of the motor driven components of the device and tocommence the PCSM return electrode test. The start/reset signal providedby this switch is derived in conjunction with the regulated +5V voltageassociated with PLD 1190 as represented at line 1266 and filtercapacitor C135. Line 1265 also is implemented with a protective networkrepresented generally at 1268 comprised of clamping diodes D100 andD101, resistors R202 and R203 and capacitor C136. Thus configured, thediodes of network 1268 provide clamps limiting the signal at line 1265to values between +5V and ground and an R-C filter is incorporated. Theprotective arrangement assures appropriate signaling withoutinterference.

[0249] Output lines 1270-1274 provide outputs effecting the energizationof the four LED illuminators at the top portion of the front panel ofconsole 64. Looking additionally to FIG. 1, the READY_LED signal at line1270 effects the illumination of LED illuminator 94; the CAPTURE_LEDsignal at line 1271 effects the illumination of illuminator LED 100; theENGZ/POS LED signal at line 1272 effects the illumination of illuminatorLED 96; the ARM_LED signal at line 1273 effects the illumination ofillumination LED 98; line 1274, carrying a COMPLETE_LED signal, effectsthe illumination of illuminator LED 102; and the PAUSE_LED signal atline 1276 effects the illumination of illuminator LED 104. These signalsare buffered at buffer 1278 and filtered by connection with sixresistors within a resistor array 1280 performing in connection with afilter associated six capacitors of a capacitor array 1282. Thesebuffered and filtered lines 1270-1275 are identified in primed fashionextending to the console upper front panel connector 1260. These LEDenergizing signals also are directed to the housing assembly LED arraysas at 60.

[0250] Pause LED 104 is illuminated under the control of PLD 1190 atsuch time as the practitioner releases footswitch 86 during a capturemode of operation wherein the pursing cables are electrosurgicallyexcited. Such excitation of the pursing cables is terminated as well asenergization of motor assembly 170 during a pause interval and theirre-energization can occur only following actuation of the arm/disarmswitch 54 on housing assembly 14, re-engagement of footswitch 86, andactuation of capture switch 56.

[0251] The handle interlock check LED 80 on console 64 is illuminated inresponse to the presence of the signal, HANDLE_LED at a terminal, of PLDcoupled to line 1230. That signal is buffered as earlier discussed inconnection with FIG. 61D, at buffer 1228 to provide an _LED_DRVOUTbuffered signal at line 1284 which reappears in FIG. 61E beingintroduced to one resistor of the array 1280 in operative associationwith a capacitor of array 1282 for filtered output at line 1306 whichextends to console 64 front panel connector 1261.

[0252] Lines 1286-1289 of the line array 1258 extending from PLD 1190carry interlock data and switching signals from the instrument 12housing assembly 14. In this regard the above-noted interlock signal,INTERLOCK_ID, is one providing for the passage of current through acoding resistor mounted within the housing assembly 14 to assure properinterconnection with connector 67 (FIG. 1). To protect interlock line1286, a protective network, represented generally at 1290, is providedwith it. Configured identically as network 1268, network 1290 isimplemented with clamping diodes D102 and D103, resistors R204 and R205and capacitor C137.

[0253] Line 1287 carries the signal representing an actuation of theenergize/position switch 54 mounted upon housing assembly 14. Thatsignal, identified as “ENGZ/POS_SW”, is submitted from connector 1262through a protective network represented in general at 1292 to PLD 1190.Network 1292 is identical to network 1268 and comprises clamping diodesD104 and D105, resistors R206 and R207 and capacitor C138. Next belowline 1287 is line 1288 carrying the output signal, “ARM_SW” of the armswitch 54 mounted upon housing assembly 14. This signal extends througha protective network identified generally at 1294 which is identical tonetwork 1268 and comprises clamping diodes D106 and D107, resistors R208and R209 and capacitor C139. Line 1289 carries the output of the captureswitch 56 at housing assembly 14 which is identified as “CAPTURE_SW” andextends through protective network 1296 which is structured identicallyas network 1268. In this regard, network 1296 is comprised of clampingdiodes D108 and D109, resistors R210 and R211 and capacitor C140.

[0254] Additionally submitted to the housing assembly 14 via connector1262 is +5V regulated power supply at line 1298, which is filtered bycapacitor C141, and LED energization signals provided at theearlier-described five lead array 1300. From the bottommost lead lookingupwardly, the array 1300 includes a line input to the ready LEDemanating from line 1270; a line input to the capture LED emanating fromline 1271; a line input to the energize/position LED emanating from line1272; a line input to the arm LED emanating from line 1273; and a lineinput to the capture complete LED emanating from line 1274. The inputsto connector 1262 correspond with the inputs described earlier inconnection with FIG. 36A at arrow 632.

[0255] Connector 1261 extends to the harness components described inconnection with FIG. 36A at line pairs 636, 638 and 640. Those linepairs are components of a harness extending to respective LEDs 84, 80and 78 in the lower portion of the front panel of console 64 asillustrated in FIG. 1. Input leads to power LED 84, connector LED 80,and PCSM fault LED 78 are configured with +5V and respective resistorsR212-R214 as shown at respective lines 1302-1304. The power LED returnline is shown as configured with capacitor C142 extending to ground andits input line extends through resistor R212 to +5V and is filtered bycapacitor R143. The handle (housing assembly 14) connector return isshown at the above noted line 1306 which is under the control of PLD1190 providing a low true condition at that line to effect illuminationof LED 80. Correspondingly, the dispersive electrode 68 return (PCSM)fault LED 78 is illuminated in flashing fashion by imposition of a lowtrue pulsing condition at line 1307 under the control of PLD 1190. Thatline is activated from PLD 1190 at line 1275 (PSCM_LED), the signalbeing treated at buffer 1278 and a resistor at 1280 in association witha capacitor at array 1282.

[0256] The +5V regulated power supply discussed in connection with FIGS.61A-61E is derived at the control board 624 by the circuit illustratedin FIG. 62. Looking to that figure, a type LM2940CT-5.0 regulatormarketed by National Semiconductor, Inc. of Sunnyvale, Calif., is shownat 1310 coupled to a +12V input at line 1312 and configured withcapacitors C144-C146 and diode D10 to provide the noted regulated +5Vsupply at line 1314. The +12V input is derived at control board 624 asdiscussed in connection with FIG. 67.

[0257] Referring to FIG. 63, a network for determining the presence of alow voltage power supply under-voltage condition as presented to PLD1190 at line 1255 is represented. Looking to the figure, the above-noted+12V power supply is treated and reduced by a network including resistorR215, capacitor C147, diode D111 and passive operational amplifier 1316having a feedback configured output at line 1318 directed to one inputof a comparator 1320. Comparator 1380 may be a type LM358D marketed byNational Semiconductor, Inc. of Sunnyvale, Calif. The reference input tocomparator 1320 is derived at a divider network coupled to the noted+12V supply and configured with resistors R216-R219 and capacitor C148to provide a reference input at line 1322. Device 1320 is configuredwith +5V input and capacitor C149 to provide a low logic true output atline 1255 in the event of an under-voltage condition. Note in thisregard that line 1255 is coupled through pull-up resistor R220 to +5Vsupply.

[0258] Referring to FIG. 64, a filtering network is revealed whichprovides an RC filtering of the inputs and outputs associated with PLD1190 and provides those filtered signals along with power supply inputsto a connector 1324 providing connection from the control board 624 tothe power board 614 as represented in general at arrow 626 in FIG. 36A.In the figure, the high voltage over-voltage signal, the d. c. linkvoltage over-voltage signal and the d. c. link voltage under-voltagesignal at respective lines 1244, 1235 and 1234 are received fromconnector 1324 and coupled via respective pull-up resistors R221-R223 to+5V source. Additionally, the signals so received are filtered by thediscrete resistors of multi-resistor component 1326 and respectivefilter capacitors C15-C152. Line 1212, carrying the reset output; line1236, carrying the d. c. link relays output; line 1237, carrying the d.c. link enable signal; line 1241 carrying the high voltage precursorenergization command signal; and line 1242 carrying the high voltagecapture command signal are each treated by discrete resistors withinmulti-resistor component 1326. Lines 1237, 1241 and 1242 additionallyare coupled to +5V source through a pull-up resistor withinmulti-resistor component 1328 as provided by three line array 1330.Divided voltages are provided from resistor array 1332 to the connector1324 and +12V source and ground inputs are submitted to the connectorfrom opposite sides of capacitor C153.

[0259] The high voltage over-current signal at line 1245; theover-temperature signal at line 1254; the motor forward stall signal atline 1248; and the footswitch and vacuum switch actuation signalsrepresented in general at arrow 1264 and labeled “OPTO_SW” are filteredby discrete resistors within multi-resistor component 1334 andrespective capacitors C154-C157. Of this line grouping, lines 1245, 1254and the footswitch and vacuum switch lines represented in general at1264 are coupled through discrete pull-up resistors within component1328 to +5V source.

[0260] The RF inverter enable command; boost mode command; motor forwardcommand; and motor reverse command are treated by discrete resistorswithin multi-resistor component 1334. Of this grouping, lines 1250 and1251 are coupled to +5V source through pull-up resistors withinmulti-resistor component 1328.

[0261] The motor on input; motor engaged input; motor reverse stall; andthe overpower input at respective lines 1252, 1253, 1249 and 1256 aretreated by discrete resistors within a multi-resistor component 1336 andfiltered by respective capacitors C200, C201, C202 and C203. A filterresistor R231 is coupled with line 1253. Of these lines, lines 1252 and1253 additionally are coupled to +5V source through discrete pull-upresistors within multi-resistor component 1328.

[0262] Referring to FIG. 65, the circuit driving speaker 646 andadjusting its volume with a potentiometer represented generally at 438in FIG. 36A is revealed. The latter figure reveals a line pair 648extending to speaker 646. That line pair is coupled with a connectorshown in the instant figure at 1338. Correspondingly, the three linearray 650 extending from potentiometer 438 is coupled to a connectorshown in FIG. 65 at 1340.

[0263] The PLD derived tone signal line 1342 reappears in the instantfigure, is asserted via resistor R224 to potentiometer 438 incombination with a ground provided in conjunction with line 1344 andresistor R225. A volume input, filtered at capacitor C158, is thenprovided at line 1346. Line 1346 is directed to an amplification stageincluding operational amplifier 1348 configured with +5V regulated powersupply, capacitor C159 and feedback line 1350. An output is provided atline 1352 incorporating resistor R226 and extending to an oscillatornetwork represented generally at 1354 including a type LM386N-1amplifier component 1356 configured with resistors R227 and R228,capacitors C160-C164 and +12V power supply to provide a tone output atline 1358. That tone output is provided whenever electrosurgical cuttingis taking place either by the precursor electrodes or the pursingcables. Additionally, the tone is pulsed in the event of a failureoccurring in the PCSM testing of dispersive return electrode 68.Amplifiers as at 1356 are marketed by Analog Devices, Inc. of Norwood,Mass.

[0264] FIGS. 66A-66C should be considered together in the manner labeledthereon. These figures illustrate the test signal generation andswitching involved in self testing and fault testing with respect to thedispersive return electrode 68. The circuit shown is a component of thePCSM circuit described in conjunction with block 528 in FIG. 34. ThisPCSM test is carried out at the very commencement of a procedure andfailure of the test will prohibit the procedure from being carried outalong with the development of pulsed warning signals of both an auraland visible variety in conjunction with speaker 646 and LED 78. Lookingto FIG. 66B, a connector 1360 is provided which, as illustrated inconnection with FIG. 36A couples to line pair 628 and 629 which extendto power circuit board 614 and, in turn, from that power circuit boardextend via line pair 654 to the return electrode connection asrepresented at block 652. Connection RE1 is represented in FIGS. 66B atline 1362 which is coupled through resistor R229 to ground. ConnectionRE2 is represented at line 1363 which is connected through resistor R230to ground. The circuits represented by RE1 and RE2 in general extendfrom electrode pads 70 and 72 to return to the high voltage output stage520 but are tapped for the instant testing purposes. PCSM circuit 528functions to impress about a 50 KHz low voltage signal across pads 70and 72 to verify that dispersive return electrode 68 is properlyconnected to the patient. In general, the testing evaluates with respectto a resistance tolerance, for example, between about 20 and about 80ohms. A resistance representation less than the former indicates ashorting condition and a resistance above the latter represents anon-connection. Those resistance values may be varied in accordance withthe desires of the designer.

[0265] Looking to FIG. 66A, the oscillator network deriving theabove-noted 50 KHz frequency is represented in general at 1364. Network1364 is comprised of operational amplifier 1367 configured inconjunction with resistors R233-R237; capacitors C167-C170;complementary amplifier 1366 configured with resistors R238-R241,capacitor C171 and the potentiometer frequency adjusting network 1368; apower supply input 1369; transistor Q30 and diode D112. Potentiometer1368; is configured in conjunction with capacitor C172 and resistorcomponents R242-R244. Input device 1369 may be provided as a typeREF-02C/AD marketed by Analog Devices, Inc. of Norwood Mass. The 50 KHzoutput developed by network 1364 is provided at line 1370 and isdirected through input resistor R245 to an amplification stagerepresented generally at 1372 functioning to adjust the 50 KHz signal toabout 7V, RMS or 12V peak-to-peak. The stage 1372 is implemented with anoperational amplifier 1374 configured with resistors R246-R249 andcapacitors C173-C175. The treated 50 KHz output is provided at line 1376which is filtered at resistor R250 and capacitor C176. Looking again toFIG. 66B, line 1376 is seen to be tapped at line 1378 to provide an“OSC_OUT” signal. Following the tap at line 1378, line 1376 incorporatesa resistor R250 having a value of about 50 ohms and extends to anoppositely disposed tap identified at 1380, labeled “50 KHz”. Extendingbetween taps 1378 and 1380 is a sequence of four relay implementednetworks represented in general at 1380-1383.

[0266] Looking to network 1380, relay K12 is seen to be connectedbetween lines 1384 and 1385. It is actuated by PLD 1190 by a signalultimately developed at line 1386 incorporating resistors R251 and R252and extending to the gate of pnp transistor Q31. Transistor Q31 isconfigured with diode D115 and resistor R253 to energize the solenoidcomponent of relay K12 in response to a signal impressed from line 1386.This functions to couple the 50 KHz signal at line 1376 and ground torespective lines 1362 and 1363 to carry out the PCSM test. This testoccurs upon practitioner actuation of start/reset switch 92 (FIG. 1).

[0267] Looking to relay network 1381, relay K13 is connected betweenlines 1388 and 1389, the latter extending to ground and the formerincorporating a 200 ohm resistor R254. Relay K13 is closed in responseto an actuation signal imposed ultimately from PLD 1190 at line 1390.Line 1390 incorporates resistors R255 and R256 and is connected to thegate of pnp transistor Q32. Transistor Q32 is configured with diode D116and resistor R257 to effect the energization of the solenoid componentof relay KI 3, closing it and connecting a 50 KHz signal at line 1376through resistor R254 to ground to provide a high resistance self test.Looking to relay network 1382, relay K14 is seen to be connected withthe 50 KHz signal at line 1376 by line 1392 and with ground via line1393. Line 1392 incorporates a 49.9 ohm resistor R258. The solenoidcomponent of relay K14 is energized to close the relay in response to asignal from PLD 1190 ultimately presented at line 1394. Line 1394incorporates resistors R259 and R260 and extends to the gate of pnptransistor Q33. Transistor Q33 is configured in conjunction with diodeD117 and resistor R261 to energize the solenoid component of relay K14when turned on in response to the signal at line 1394. This diverts the50 KHz signal across the 49.9 ohm resistance at resistor R258 from line1376 to ground.

[0268] Looking to relay network 1383, relay K15 is seen to be coupledbetween line 1396 connected to line 1376 and line 1397 coupled toground. The solenoid component of relay K15 is energized upon theoccurrence of a signal ultimately derived from PLD 1190 and asserted atline 1398. Line 1398 incorporates resistors R262 and R263 and is coupledto the gate of pnp transistor Q34. Transistor Q34 is configured withdiode DI1 8 and resistor R264 to energize the solenoid component ofrelay K15 upon being turned on from line 1398. This couples line 1376 toground through lines 1396 and 1397, providing a self test representing ashort circuit.

[0269] Referring to FIG. 66C, actuation lines 1386, 1390, 1394 and 1398are seen to be coupled to the collector output stages of respectiveopto-couplers 1400-1403. The emitter components of the outputs ofcouplers 1401-1403 are coupled to ground via line 1404 and each coupleris coupled with +12V source through respective resistors R265-R268. Theanode inputs to opto-couplers 1400-1403 are coupled through respectiveresistors R269-R272 to +5V source at line 1406, while the cathode sideinputs thereof are coupled with respective input lines 1408-1411.Returning momentarily to FIG. 61D the latter line grouping isrepresented at line array 1232 as providing the buffered outputs of thelines of line array 1222 extending from PLD 1190. Thus, the returnelectrode 68 test, as well as the PCSM self-test are carried out underthe command of PLD 1190. It may be noted that relay KI5 of network 1383is energized to short the signal at line1376 during those intervalswherein the tests asserted from networks 1380-1383 are not being carriedout, even though relay K12 will be open.

[0270] Referring to FIG. 67, an isolated power supply utilized togenerate the noted +12V is illustrated. This power supply is configuredabout a supply component 1412, provided as a type NMS1212 devicemarketed by Newport Components, Inc. by Milton Keynes, GB. In effect,device 1412 converts +12V to +12V and −12V. It is configured withinductors L16-L19 and capacitors C177-C182 to provide an isolated +12Vat output 1414 and an isolated −12V at output 1415. Device 1412 isprovided a +12V input at line 1416 from power transistor Q36, the sourceof which is coupled to +12V from lines 1418 and 1419 and the gateterminal of which is coupled with line 1420 to line 1419. Line 1419incorporates resistors R273 and R274 and is coupled with the collectionof NPN transistor Q37, the emitter of which is connected to ground.Transistor Q37 is gated on to enable the power supply 1412 by aPCSM_ENBL signal asserted from PLD 1190 at line 1224 through baseresistor R275. Line 1224 is coupled through resistor R276 to ground andis seen extending from PLD 1190 in FIG. 61A.

[0271] Referring to FIGS. 68A and 68B, which should be considered in theorientations as labeled thereon, a window defining detection orcomparison circuit is illustrated which evaluates the actual PCSM testfrom network 1380 (FIG. 66B) as well as the self test of networks1381-1383. In general, the ohmic window representing a valid dispersiveelectrode 68 connection will reside between about 20 and 80 ohms.Referring to FIG. 68A, the taps 1378 and 1380 as described in connectionwith FIG. 66B are shown to extend to the inputs of a differentialamplifier 1422. Amplifier 1422 may, for example, be a type AMP02FSdevice marketed by Analog Devices, Inc. of Norwood, Mass., and isimplemented with +12V and −12V and capacitors C185 and C186. Thusconfigured, device 1422 responds to the floating signal at resistor R250(FIG. 66B) and provides a single ended signal to ground at output line1424. This A. C. signal at line 1424 then is submitted through inputresistor R277 to a precision rectifier represented in general at 1426.The rectifier 1426 provides rectification without diode drop phenomenaand is seen to comprise operational amplifier 1428 configured withresistor R278, diodes D119 and D120 and capacitors C187 and C188. The d.c. signal at output line 1430 then is proportional to the current in thereturn electrode or to the test evaluations from networks 1381-1383 andis impressed across capacitor C189. A resistor R279 extends between line1430 and ground and functions for the selective discharge of capacitorC189.

[0272] The d. c. signal at line 1430 is directed to the positive inputof a comparator 1432 and via line 1434 to the negative input of acorresponding comparator 1433. Reference inputs to these comparators1432 and 1433 are provided from line 1436 and +12V which incorporatesreference defining resistors R280-R282. The reference inputs are seen tobe connected additionally with filtering capacitors C190 and C191, whilethe +12V input to comparator 1432 is filtered at capacitor 0192.Capacitors 1432 and 1433 may be provided as type LM319M devices marketedby National Semiconductor, Inc. of Sunnyvale, Calif.

[0273] When the current represented at line 1430 corresponds with aresistance falling within a window defined between a lower threshold offor example 20 ohms and an upper limit of for example, 80 ohms, then apositive voltage signal will be impressed from resistor R283 at line1438. Looking to FIG. 68B, line 1438 is seen to extend to the anode ofthe input side of an opto-coupler 1440. The collector component of theoutput of opto-coupler 1440 is coupled with +12V through resistors R284and R285, while the emitter output thereof is provided at line 1226which is coupled through resistor R286 to ground. Line 1226 serves toapply the signal thereat representing a valid test, “PCSM_VALID” to PLD1190 as shown in FIG. 61A.

[0274] Referring to FIG. 69, a schematically portrayed timing diagram isprovided which describes the control over motor assembly 170 in terms oftime and the corresponding application of boost and normal cuttingvoltages at the pursing cables 300-304 during the operation of thecapture component. The diagram utilizes an arbitrarily established onesecond point-in-time at line 1442. Extending backwardly in time fromline 1442, a time increment represented as t₀, is line 1443 representingthe instant-in-time when the practitioner will have actuated the starttissue capture switch 56 on instrument housing assembly 14 or footswitch86 c (FIG. 1) by holding one or the other in a continuously depressedcondition. Arm/disarm switch 54 or footswitch 86 b will have beenactuated momentarily earlier. Accordingly, at the time represented atline 1443, motor assembly 170 is energized. Transition component 176will be rotating and the yoke 184 of the transfer assembly 180 will bemoving forwardly but will not have touched drive member ears 134 and136. It is during a test interval of one-half second within thisinterval, to, that the test described in connection with FIG. 50 iscarried out to assure that the motor assembly and transition componentare working properly, i.e., not binding or experiencing anomalies. Ingeneral, the motor current draw status should be one wherein the motoris not drawing more than 23 milliamps. At the time represented at line1442, the control as described in connection with FIG. 51, determinesthat the yoke 184 has engaged ears 134 and 136. At this point-in-time,the motor assembly 170 is de-energized, and following a switching delay,t_(s), electrosurgical cutting current at a boost voltage level isapplied to the pursing cables 300-304. The commencement of applicationof this electrosurgical boost current is represented at dashed line 1444the height of which indicates the level of boost voltage. Boost currentis applied during the period, t_(boost), for an interval of 100 to 1000ms and preferably for an interval from about 250 ms to 750 ms. The boostvoltage, V_(boost) is selected within a range extending from about 1100volts, peak-to peak to about 2000 volts, peak-to-peak, and, preferablyis within a range extending from about 1100 volts, peak-to-peak to about1300 volts, peak-to-peak. At the termination of the boost interval asrepresented at dashed line 1445, the electrosurgical energy is droppedto a normal cutting voltage level, V_(cut) as represented at dashed line1446. The cut voltage, V_(cut) is selected within a range extending fromabout 700 volts, peak-to-peak to about 1200 volts, peak-to-peak, and,preferably, within a range extending from about 800 volts, peak-to-peakto about 1000 volts, peak-to-peak. Just following the alteration ofvoltage level to, V_(cut), at a time interval represented as tdelay, andas indicated by solid line 1447, the motor assembly 170 again isenergized for an interval of time required to complete the capture ofthe tissue specimen, an interval which will vary depending upon themaximum diametric extent defined by the outwardly extending leafs. Ingeneral, where that diameter is about 10 mm, t_(end of capture) willoccur at about 5 to 6 seconds. By contrast, a maximum diametric extentof about 20 mm will involve about 10-12 seconds of time tot_(end of capture). During the interval of driving the capture componentthe load characteristic or current draw of motor assembly 170 ismonitored as described in connection with FIG. 51. Where that loadcurrent falls below a predetermined threshold, a fault condition obtainswith a flashing of all LEDs. A termination of motor forward drive isdetermined by the forward stall detection as described in connectionwith FIG. 52 and is indicated by the solid line 1448. Line 1448 alsocoincides with the termination of electrosurgical cutting current asrepresented by coincident dashed line 1449. In general, the rate ofspeed of deployment of the capture component leafs may range from aboutone mm per second to 5 mm per second and preferably will be in a rangeof about 2.5 mm per second to 4 mm per second. This movement rate isexhibited at transfer assembly 186 and engaged drive member 324.

[0275] Control over the cutting energy supplied from the electrosurgicalgenerator function to the pursing cables 300-304 is predicated interalia, upon both a conventional design approach wherein the powerdeveloped must be effective to cut while not being of an extent causingexcessive damage to tissue adjacent the cut, the instrument or therecovered tissue specimen. With system 10, however, additional criteriaarise. The active electrode, when manifested as the tissue encounteringportions of cables 300-304, is changing in surface area extent duringthe procedure. It initially commences to be excited under boost voltagehaving a geometry somewhat resembling a point source. Then it increasesin peripheral extent resembling a gradually expanding line source,whereupon it then returns to assume a geometry again approaching a pointsource. Thus the system 10 calls for an increasing power output duringthe initial expansion, with surface area increase, followed by adecreasing power output characteristic as contracting pursingencapsulation occurs. Additionally, at the commencement of theprocedure, the active electrode assembly whether precursor electrodes orpursing cables, is embedded in tissue and boost voltage is called forduring a boost interval adequate to cause the commencement of an arcextending between the cutting portions of cables 300-304 and the tissuebeing cut. In effect, it is this arc and not the cables that create thecut. The active cable portions as well as the precursor electrodesmerely slide within a vapor developed from the adjacent tissue celllayers.

[0276] Conventional electrosurgical generators are designed to performin conjunction with an active electrode of fixed configuration orgeometry such as a blade or rod. Development of a necessary cutting arcis achieved by the technique or experience of the surgeon who causesinitial arc formation or creation by moving the active electrode towardthe targeted tissue until the arc forms, for example, at about onemillimeter. Looking to FIGS. 70A and 70B, this technique is portrayed. Apatient is depicted at 1450 whose back is abuttingly engaged with alarge dispersive electrode 1451 which provides a return to anelectrosurgical generator 1452. Generator 1452 feeds cutting energy toan active electrode 1453 of fixed geometry.

[0277] To achieve arc commencement, the electrosurgical generator outputmust confront an impedance of adequate range, for example, 1300 to 1500ohms. This impedance is resistant in nature and comprises theresistance, R_(tissue), exhibited by the body of the patient 1450, asrepresented by the distance from B to C, the value ranging from about300 ohms to 500 ohms, in combination with the impedance or resistancedeveloped by the active electrode spacing from tissue. FIG. 70Billustrates, in enlarged fashion, that spacing, L_(g), as the distancefrom A to B. Looking to FIG. 71, this resistance, R_(AB) is plotted atdashed line 1454 with respect to variations in the distance, L_(g). Notethat at values of L_(g), greater than about 2 millimeters, theresistance RAB approaches infinity and no arc is developed. However, asthe active electrode of fixed configuration approaches a distance, L_(g)of value of about one millimeter, a resistance of about 500 ohms to 1000ohms is witnessed which, when combined with the resistance, Rtissue (Bto C) permits an arc to be formed. With the proper resistance,R_(total), represented from A to C, the cutting arc will be sustained inaccordance with the generalized expression: R_(total)=R_(tissue) andR_(arc). With the above arrangement, conventional electrosurgicalgenerators are operated in conjunction with a fixed output power and avariable applied voltage. The output power levels thus are maintainedwithin a safe range, for example, from about 80 watts to about 100watts.

[0278] The equivalent of the arc formation otherwise created byelectrode spacing carried out with the technique of the surgeon isachieved with system 10 even though the active electrode initially isembedded in tissue with no initial spacing available. Application of theshort term (t_(boost)) boost voltage (V_(boost)) causes a vaporizationof the tissue solid structure adjacent the initially exposed and tissueembedded active portions of cables 300-304. This evokes the equivalentof an initial spacing to achieve requisite impedance for arccommencement. The interval of application of the boost voltage may be ofa fixed duration, for example, about 500 milliseconds or less (about 250milliseconds to about 375 milliseconds currently being preferred) or maybe defined by the creation of the arc following the application of thisboost voltage. The impedance change, R_(total), at the formation of thearc represents a quite abrupt alteration and results in acorrespondingly abrupt drop in output current flow. Accordingly, theformation of the arc is readily detected to carry out boost voltageapplication termination.

[0279] Referring to FIG. 72, the performance of system 10 in connectionwith an experiment carried out using slab bacon and a capture maximumdiametric extent of 10 millimeters is portrayed. In the figure, totalresistance in terms of ohms as computed is plotted with respect to time.Additionally, applied, peak-to-peak voltage is plotted with respect tothat time. Further, the current witnessed at d.c. motor 170 a (as seenin FIG. 4) is set forth. At the commencement of the procedure, prior tothe application of boost voltage the total resistance was equal to thetissue resistance, R_(tissue) as earlier described in connection withthe distance B - C in FIG. 70A. That 500 ohm level is represented atdashed line segment 1455. Boost voltage was applied to the cableelectrodes to commence the boost interval at a boost voltage of 1400volts peak-to-peak. That boost voltage was imposed for an interval,T_(boost) of 500 milliseconds, whereupon the applied voltage abruptlydropped as represented at solid line segment 1457. During the boostinterval, following about 200 milliseconds, as represented at dashedline segment 1458 and vertical dashed line segment 1459 an arc wasformed and total resistance abruptly elevated to about 1500 ohms at apoint in time near the termination of the fixed boost interval, asrepresented at line segment 1457 the applied voltage was dropped to anormal cutting voltage level represented at horizontal solid linesegment 1460. This applied normal cutting voltage is seen to have beenat a level of 1000 volts peak-to-peak. Essentially simultaneously, asrepresented at vertical dashed line segment 1461 motor 170 a wasenergized following a head start interval from the application of boostvoltage identified as t_(hs). With the energization of the motorassembly 170, the leafs commenced to be extended as the cables 300-304began to be played out toward a peripheral extent of maximum diameter.As this occurred, the length and consequent surface area of the cablesengaged in active cutting of tissue expanded and the corresponding totalresistance commenced to drop as represented by the dashed curve segment1462. When the maximum peripheral extent of the leaf tip portions andactive cable cutting length reached a maximum value, as represented atvertical dashed line 1463 resistance reached a lowest value and appliedcurrent reached a maximum value with concomitant power increase.

[0280] As the time interval of the procedure continued beyond the timerepresented at vertical dashed line 1463, the active surface area ofcables 300-304 employed in cutting tissue reduced as pursing ensued andthe effective cable length engaged in tissue cutting reduced as totalresistance again increased as represented by the curved dashed linesegment 1464. During this interval, the d.c. motor current whichcommenced at line segment 1460 gradually increased as represented atdashed line segment 1465 until motor stall threshold was reached asrepresented at the current level 1466. Motor drive and normal cuttingvoltage were terminated abruptly as represented at respective dashedline segments 1467 and 1468. Following the procedure the totalresistance returned to the value of the tissue resistance, R_(tissue) asrepresented at horizontal dashed line segment 1469.

[0281] Referring additionally to FIG. 73 (adjacent FIG. 62), a plot ofpeak current output occurring during the interval represented by theprocedure carried out in connection with FIG. 72 is revealed. In thefigure, at the commencement of the procedure, a very abrupt current risefor a very short interval of about 200 milliseconds is revealed followedby an abrupt drop. As the total resistance dropped at the timerepresented at vertical dashed line 1463, current rose again to a peakand thereafter diminished to about the same level it assumed followingthe formation of an arc at the termination of the initial current spike.K is during that current spike that the effective initial spacing iscarried out by vaporization of tissue cells. The plot of FIG. 73 alsomay be considered to correspond with power dissipation during theprocedure.

[0282] Returning to FIG. 72, and recalling that with system 10, powerapplied from the electrosurgical generator is varied in accordance withthe application of boost voltage and with the changing of the cableelectrode geometry for the example at hand, power dissipation may beevaluated. The commencement of the application of boost voltage isrepresented at line 1456, a tissue resistance of 500 ohms wasencountered. Accordingly, until the arc was formed, under an appliedboost voltage of 1400 volts peak-to-peak, a power dissipation (computedas based upon RMS voltage) of about 500 watts occurred. However thatpower was produced in a highly constricted region for the very shortinterval occurring until the arc was formed as represented at dashedline 1459, for example, an interval of about 200 milliseconds. As soonas the arc was formed, as represented at dashed line 1459, the impedancerepresented by the arc was added to the 500 ohms tissue impedance andthe power dissipation dropped to about 167 watts which, althoughslightly higher, remained only until the removal of boost voltage asrepresented at vertical line 1457. Normal cutting voltage at 1000 voltspeak-to-peak then ensued with a power dissipation of about 85 watts.However, now the expansion of the active electrode commenced, poweragain rose as the total resistance dropped to about 800 ohms as thecable length enlarged and the maximum peripheral extent of the leadingedge of the capture component was reached as represented by the dashedlocator line 1463. Accordingly, the power will have elevated from about85 watts to about 159 watts. However, the 159 watt power value is oneassociated with a relatively widely disbursed line source electrode atits maximum linear extent. As pursing activity then ensued, that linearextent diminishes toward a point value and power dissipation alsodiminishes to again approach 85 watts at the termination of capture.

[0283] As is apparent from the forgoing, it is possible to applyelectrosurgical energy at the boost voltage level (e.g., 1100 volts,peak-to-peak) continuously throughout the procedure. In effect, theboost interval, t_(boost) is extended to encompass the entire time ofthe procedure whether positioning with precursor electrodes or capturingwith pursing cables. However, the consequence of so expanding the boostinterval is the potential generation of excessive power during thebiopsy procedure which results in greater depth of thermal injury to thebiopsy specimen and surrounding healthy tissue.

[0284] Unlike conventional electrosurgical cutting systems, the instantgenerator sustains the essential cutting arc by employing a constantvoltage output. Conventional feedback loop approaches for developingsuch control typically will evoke a non-stable oscillatory outputunsuitable for electrosurgical cutting. Such instability is inconsequence of the negative dynamic impedance characteristic of an arc.By employing the above-discussed inner and outer feedback loop inconjunction with control to the D. C. link inverter 490, stable,constant voltage-based control is achieved.

[0285] FIGS. 74A-74G combine as labeled thereon to provide a flow chartdescribing the operation of the instant system. In the discourse tofollow, the term “handle” refers to instrument 12; the term “precursorelectrode” refers to the electrode assembly as at 228; and the term“controller” refers to console 64. Cueing icons representing givenswitch functions, test results or operational modes are provided, whereappropriate adjacent switches and elsewhere an instrument 12 and console64. Looking to FIG. 74A, the procedure starts as represented at block1472 and line 1473 providing for the connection of connector 66 of cable62 to console connector 67. Next, as represented at block 1474 and line1476 controller 64 is turned on by actuating front panel switch 82. Asthis occurs, a handle interlock test is carried out as described inconjunction with line 286 of FIG. 61 E. In this regard, an interlockcurrent is caused to pass through a 10 kohm coding resistor present inthe instrument 12 housing assembly 14. If the test for this interlockconnection is passed, then the green LED 80, above the console cableconnector 67 will be illuminated as represented by the query posed atblock 1478. Where LED 80 is not energized, then the procedure reverts asindicated at line 1480 and block 1482, the practitioner beingpre-instructed to check for a proper handle (housing assembly 14)connection and if that connection is proper, then the instrument 12 isreplaced. For either of these improper conditions, the procedure loopsto commencement block 1470 as represented at lines 1484 and 1486. Wherethe query posed at block 1478 indicates that proper handle (housingassembly 14) connection is present and the green LED 80 is illuminated,then the procedure continues as represented at line 1488 and block 1490.Turning on switch 82 also causes the carrying out of the self testfeatures of PCSM system 528 as described in conjunction with networks1381-1383 in connection with FIGS. 66A-66B and 68A-68B.

[0286] Block 1490 calls for an actuation of the console mountedstart/reset switch 94. This causes the motor assembly 170 to beenergized in a reverse sense to cause the rotation of translationcomponent 176 and the driving of transfer assembly 180 rearwardly untilthe nut 182 engages bulkhead surface 248. As described in conjunctionwith FIG. 53, this derives a MOTOR_REV_STALL signal, whereupon the motorassembly 170 is energized in a forward sense for 0.125 second to relaxthe thus caused axial load. This dual energization procedure ismonitored. As represented at line 1492 and block 1494, a determinationis made as to whether the green LED below the start/reset icon on thehousing assembly 14 as well as the corresponding green LED 94 at console64 is illuminated. Where those LEDs are not illuminated, the activitydescribed at block 1490 failed and the procedure reverts as representedat line 1496 and block 1498, the practitioner having been pre-instructedthat a faulty cable or “handle” is at hand and the procedure reverts tostarting block 1470 as represented at lines 1500 and 1486. Actuation ofswitch 94 also causes the carrying out of the test for proper connectionof dispersive return electrode 68 by the PCSM system 528 as discussed inconjunction with network 1380 in connection with FIGS. 66A-66B and68A-68B. A failure to pass this test results in the flashing of red LED78, generation of a pulsing sound output, and the procedure is halted.

[0287] Where the query posed at block 1494 results in an affirmativedetermination with the illumination of the noted green LEDs, then, asrepresented at line 1502 and block 1504, the practitioner inserts thedisposable probe component 108 (FIG. 2) into the housing 15. Properinsertion is assured inasmuch as disposable component 108 cannot beinserted within the housing 15 to create housing assembly 14 unless theindexing pin 116 is aligned for slidable insertion within the slot 118.(See FIG. 4). Additionally, color codes on the disposable components aswell as on the housing 15 are provided to assure proper registry. Forexample, one such color code is shown at 252 in FIG. 8. The particulardisposable component 108 selected for the procedure will, as describedin connection with FIGS. 14, 28, 29 and 31, 32 be prefabricated with aposition for cable stop 322 selected with respect to the maximumeffective diametric extent of expansion and forward extension of thecapture component leafs. Practitioner selection is made with respect tothe predetermined size of the tissue volume desired to be removed. Ingeneral, the pursing cable and leafs will extend through healthy tissuesurrounding a targeted lesion. This will avoid seeding complications andthe like upon removal of the biological specimen. The program thencontinues as represented at line 1506 and block 1508 providing for theadministration of a local anesthetic at the skin level in the region ofthe intended biopsy. This step is performed several minutes before askin incision is made to commence probe positioning. Following theadministration of the anesthetic agent, as represented at line 1510 andblock 1512 a cold scalpel is employed to make a skin incision to a depthof about 4 mm and a length approximately 2 mm wider than the maximumwidth of the precursor electrode. Then, as represented at line 1514 andblock 1516 switch 46 of the smoke/steam evacuator assembly 44 is turnedon or footswitch 48 is actuated (FIG. 1). Next, as represented at line1518 and block 1520 the tip 32 of the delivery cannula 22 of theinstrument 12 is positioned within the incision made in conjunction withblock 1512 at a location wherein the precursor electrodes are at leastabout 3 mm below the surface of the skin.

[0288] The procedure then commences a positioning mode as represented atline 1522 and block 1524. During this mode, the practitioner, usingultrasound, stereotactic, upright mammography guidance or palpation,presses the energize/position switch button 55 on the housing assembly14 or actuates footswitch 86 a to cause the application ofelectrosurgical current to the precursor electrodes at the tip 32. Atthis juncture in the procedure, the control assembly carries out aninterlock form of test to assure that the vacuum system turned on atblock 1516 is indeed on and working. This test provides an assurancethat steam will not migrate along the outer surface at delivery cannula22. Accordingly, as represented at line 1526 and block 1528 a query ismade as to whether the vacuum system is on. In general, this test iscarried out in conjunction with a vacuum sensor 51 combined withcomponent 44 (FIG. 1). Where no vacuum is sensed, as represented at line1530 and block 1532, the system turns on all cueing LEDs and theprocedure dwells as represented by line 1534, until the vacuum system isactivated. Where the vacuum system is in proper order and activated,then as represented at line 1536 and block 1538, the practitioneradvances the tip 32 of the probe to a position just proximal to thetarget lesion. Yellow LED outputs adjacent switch 55 will be illuminatedas well as yellow LED 96 at console 64. Additionally, a steady audibletone is produced from loudspeaker 646 (FIG. 36A). As discussed inconnection with FIG. 28, the distance between the tip 32 of the probeand the center of the target lesion (Ls) depends upon the diameter ofthe intended tissue volume capture and the maximum diametric extent ofthe probe (Dc). It may be recalled that the maximum effective diametricextent is reached as the pursing cables draw cable terminator component296 into engagement with the cable stop 322 (see FIG. 28). In general,the distance Ls will equal about 0.6*Dc.

[0289] The procedure then continues as represented at line 1546 andblock 1548. At this juncture of the procedure, the practitioner must beassured that tip 32 of the delivery cannula 22 is in proper position andorientation for carrying out a specimen capture. Accordingly, asrepresented at line 1550 and block 1552, a determination is made as towhether the probe tip 32 is in a correct position. If it is not, then asrepresented at lines 1554 and 1556, the procedure reverts to line 1522and the positioning mode represented at block 1524.

[0290] Where the delivery cannula tip 32 is in proper confrontingadjacency with the involved tissue volume, then as represented at line1558 and block 1560, an arm capture mode is entered as the practitionermomentarily presses the arm/disarm switch at footswitch 86 b or thebutton 54 on the housing assembly 14. As this occurs, the green LEDoutputs positioned adjacent switch 54 on the handle are illuminated aswell as green LED 98 on console 64. Actuation of button switch 54 orfootswitch 86 b is a prerequisite step before starting tissue capture.Should the practitioner wish to return to the positioning mode of block1524 following the actuation of switch 54, as represented at line 1562and block 1564, upon making a determination that tip 32 is not in properposition, but the arm capture mode is at hand, then as represented atline 1566 and block 1568, the practitioner presses the arm/disarmfootswitch 86 b or handle button 54 again. Then, as represented at lines1556 and 1522, the positioning mode is reentered and both the footswitch86 a and energize/position switch button 55 again are active.

[0291] If the delivery cannula tip 32 is in a correct position forentering the capture mode from the arm capture mode, then as representedat line 1570 and block 1572 the capture mode may be entered. This entryinto the capture mode starts a three stage automated sequence. As astage one, the motor assembly 170 is test energized for about one halfsecond as described at to in connection with FIG. 69. The yoke 184 willnot have engaged the ears 134 and 136 of drive member 324 for thisinitial one half second by virtue of the above-discussed spacing design.The control system monitors motor current for at least that one halfsecond. Where the proper low current levels are detected during that onehalf second (FIG. 50) this capture mode test then is satisfied. Motorassembly 170 will be de-energized upon detection of its currentcondition representing engagement of the yoke 184 with ears 134 and 136as discussed in connection with FIG. 51. As a stage two, while the motoris de-energized at this juncture, the interval t_(boost) occurs with theapplication of boost level voltage electrosurgical cutting current tothe pursing cables. This initiation of the electrosurgical cutting arcoccurs typically within about 0.25 second. Following a three-eighthssecond boost interval, the normal cut voltage described at dashed line1458 in FIG. 69 ensues. At stage three, as described in conjunction withline 1460 in FIG. 69, motor drive again is commenced to start tissuecutting and capture, an arrangement which continues until the pursingdown of the cutting cable electrode is completed. During this intervalof time, monitoring of motor load current continues (FIG. 51), and starttissue capture button 56 or footswitch 86 c are continuously actuated ordepressed to maintain the capture mode. With the depression of eitherthe start capture footswitch 86 c or the start capture switch or button56, yellow LED outputs adjacent to switch 56 on instrument 12 areilluminated as well as LED 100 on console 64.

[0292] The initial motor test run is represented at line 1574 and block1576 and the current monitoring test carried out by the circuit of FIGS.50 and 51 is represented at line 1578 and block 1580. Where the motortest carried out during the noted one half second test interval fails,then as represented at line 1582 and 1584, all LEDs on both the housingassembly 14 and the console 64 commence to flash and, as represented atline 1586 and block 1588 a handle and/or cable fault is at hand and thehandle reusable housing 15 should be replaced. The procedure thenfollows the path represented at line 1486 to block 1470 calling for arestart of the entire procedure. Where the one half second motor test asrepresented at block 1580 shows proper performance and the yoke 184 hasmade contact with ears 134 and 136 of drive member 324 (FIG. 4) then thecontrol system will have detected this motor engaged condition asdescribed in conjunction with FIG. 51 and the motor is de-energized asrepresented at line 1450 in FIG. 69. Correspondingly, as discussed inconnection with line 1454 in that figure, the electrosurgical generatorfunction is turned on with boost voltage. Preferably that boost outputis applied for three-eighths second as represented at line 1590 andblock 1592. Commencement of timing of the 0.375 second interval isrepresented at line 1594 and block 1596. Determination of the 0.375second interval is made as represented at line 1598, block 1600 and loopline 1602. At the termination of this 0.375 second interval, anaffirmative determination is made as represented at line 1604 which isseen to lead to block 1606. At this point in the procedure, as describedat dashed line 1458 and FIG. 69, normal cutting voltage is applied tothe cables of the capture component and the motor assembly 170 isenergized to start the deployment of the capture component, ears 134 and136 being driven forwardly by yoke 184. This procedure normallycontinues with the earlier-noted motor current monitoring (FIG. 51)until capture is complete. However, should the motor current level fallbelow the motor engaged threshold established as described in connectionwith FIG. 51, then a fault condition is indicated and the procedure ishalted. In this regard, loss of load related motor current levels is anindication of mechanical failure.

[0293] As represented at line 1608 and block 1610 the practitioner mayencounter some reason for pausing this capture procedure. Accordingly,if an affirmative determination is made with respect to the query posedat block 1610, then as represented at line 1612 and block 1614 a pausemode is entered. This pause mode is entered by releasing the previouslydepressed footswitch 86 c or handle button 56. The pause LED 104 onconsole 64 then is illuminated.

[0294] At such time as the practitioner is ready to resume the cuttingcapture procedure, either start capture switch button 56 or thefootswitch 86 c again is depressed returning to the capture mode. At theinitial release of either of the capture switches to enter the pausemode, the yellow LED outputs adjacent the start capture switch 56 andLED 100 will have been illuminated in a flashing or intermittentfashion. Accordingly, following a reactivation from a pause mode, asrepresented at lines 1616, the capture mode is again underway asrepresented at line 1608. Where no pause mode is entered, then, asrepresented at line 1618 and block 1620 the system looks for thepresence of a forward motor stall condition as described in connectionwith FIG. 52. As represented at the loop line 1622 extending to line1608, the motor assembly 170 and pursing cables 300-304 continue to beenergized until the forward stall is detected, such detection beingrepresented at line 1624. Upon such detection of a forward stallcondition, as represented at block 1626, a capture complete mode isentered, the capture of the target tissue or tissue volume beingcompleted and the electrosurgical cutting voltage is terminated.

[0295] Motor assembly 170 then automatically reverses to return the yoke184 to its home position. Additionally, green LED outputs positionedforwardly of switch 56 on housing 14 are illuminated as well as greenLED 102 on console 64. Next, as represented at line 1628 and block 1630a query is posed as to whether a reverse stall current threshold limithas been reached. Detection of this stall condition is described inconnection with FIG. 53. Accordingly, as the motor is energized inreverse, the system awaits that stall condition as represented at loopline 1632. Upon an affirmative determination that the reverse stallcondition is at hand, as represented at line 1634 and block 1636, thepractitioner removes the delivery cannula 22 from the patient byappropriate manipulation of housing assembly 14. During this removal,some stretching of the tissue typically will be encountered with littleor no disfigurement ensuing.

[0296] Next, as represented at line 1638 and block 1640 locking nut 24is unscrewed and the vacuum equipment is disconnected, plug 41 beinginserted into connector 40 (FIG. 1). Then, as represented at line 1642and block 1644, as discussed in connection with FIG. 30, thepractitioner retracts ears 134 and 136 to a position shown adjacentlatches 336 and 338 to establish a specimen access orientation with theleafs. That containment orientation resembles a cup or basket (FIG. 30).Then, as represented at line 1646 and block 1648, the tissue specimen isplaced in a container with appropriate solution for transport andstorage in preparation for examination by a pathologist. As representedat line 1650 and block 1652 the specimen is transported to a pathologylaboratory.

[0297] An optional arrangement is represented at line 1654 and block1656. The latter block provides for placing a radio-opaque and/orechogenic marker in the tissue at the site of the biopsy and verifyingthe position thereof using radiography or ultrasonography. Then, asrepresented at line 1658 and block 1660 the skin incision is closedusing appropriate conventional closure techniques.

[0298] Since certain changes may be made in the above method, system andapparatus without departing from the scope of the invention hereininvolved, it is intended that all matter contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

1. Apparatus for retrieving a tissue volume of given peripheral extent,comprising: a delivery cannula having an outer surface surmounting aninterior channel and extending from a proximal end portion along alongitudinal axis to a forward region having a distal end positionablein confronting adjacency with said tissue volume; a capture componentpositioned within said delivery cannula interior channel at said forwardregion, having a forward portion extending to a forwardly disposedpursing cable assembly energizable to define an electrosurgical cuttingleading edge portion, and including at least one tensionable cableextending from said pursing cable assembly into said inner channel, saidleading edge of said forward portion being extendable from said deliverycannula laterally outwardly and forwardly toward an outer peripheraldimension having a predetermined diametric extent effective to provide acircumspective positioning about said tissue volume peripheral extentand subsequently extendable while being drawn in contraction toward saidaxis by stress at said pursing cable assembly to a capture orientationenveloping said tissue volume; a housing assembly having forward andrearward portions and coupled in supporting relationship with saiddelivery cannula at said proximal end portion; a drive assemblyextending from driving engagement with said capture component to adriven engagement portion at said housing assembly and drivably movablealong said axis from a start orientation to a capture positioncorresponding with said capture orientation; and an actuator and controlassembly drivably engageable with said drive assembly to effect saidmovement thereof, responsive to control said drive assembly movement incorrespondence with said stress exhibited by said cable and including aterminal assembly for effecting said energization of said pursing cableassembly.
 2. The apparatus of claim 1 in which said actuator and controlassembly comprises a cable terminator component coupled with said cableand a cable stop member engageable therewith, said cable terminatorcomponent being drivably movable by said cable along said axis incorrespondence with said drive assembly movement, from an initialposition into engagement with said cable stop member to define saidcapture component forward portion leading edge peripheral dimension ofpredetermined diametric extent and to effect said subsequent contractionthereof by said pursing cable assembly.
 3. The apparatus of claim 1comprising a drive stop assembly engageable with said drive assemblydriven engagement portion and positioned to limit said movement alongsaid axis beyond said capture position.
 4. The apparatus of claim 1including a precursor electrosurgical electrode assembly supportedforwardly from said delivery cannula distal end and having a tissueencountering and severing portion generally extending normally to saidlongitudinal axis and configured to facilitate the said positioning ofsaid distal end in said confronting adjacency with said tissue volume.5. The apparatus of claim 4 including an arc isolating and electricallyinsulative member mounted at said delivery cannula distal end rearwardlyof said precursor electrosurgical electrode assembly tissue encounteringand severing portion.
 6. The apparatus of claim 4 in which said tissueencountering and severing portion has an effective length less than butcorresponding with said capture component predetermined diametricextent.
 7. The apparatus of claim 4 in which said precursorelectrosurgical electrode assembly tissue encountering and severingportion is configured as four discrete severing portions arrangedgenerally in quadrature about said longitudinal axis.
 8. The apparatusof claim 1 further comprising: an elongate support member extendingwithin said delivery cannula along said longitudinal axis from saidforward region into said housing assembly and secured thereto adjacentsaid rearward portion, and said drive assembly is positioned over saidsupport member and includes a drive member located within said housingassembly, and engageable with said actuator and control assembly to movefrom said start orientation along a capture region to a said captureposition and including a positioning component configured for slidableengagement with portions of said housing assembly.
 9. The apparatus ofclaim 8 comprising a drive stop assembly abuttably engageable with saiddrive member and positioned to limit said movement along said axisbeyond said capture position.
 10. The apparatus of claim 8 in which saiddrive assembly comprises a latch assembly mounted within said housingassembly within said capture region and engageable with said drivemember to limit a movement thereof along said longitudinal axis towardsaid rearward portion to a return position located forwardly from saidstart orientation.
 11. The apparatus of claim 8 in which said driveassembly drive member positioning component extends outwardly from saidhousing assembly portions to an extent wherein it is abuttablyengageable in driven relationship with said actuator and controlassembly.
 12. The apparatus of claim 11 in which said positioningcomponent is configured for hand grasping to carry out movement of saiddrive member from a said capture position toward said start orientation.13. The apparatus of claim 8 in which said actuator and control assemblycomprises: a cable terminator component mounted for movement upon saidsupport member and coupled with said cable; a cable stop member fixed tosaid support member at a predetermined stop position and abuttablyengageable with said cable terminator component; and said cableterminator component being drivably moveable by said cable from aninitial position along said axis into engagement with said cable stopmember at said stop position to define said capture component forwardportion leading edge peripheral dimension of predetermined diametricextent.
 14. The apparatus of claim 13 comprising a drive stop assemblyabuttably engageable with said drive member and positioned to limit saidmovement along said axis beyond said capture position.
 15. The apparatusof claim 13 in which: said actuator and control assembly terminalassembly includes an electrical contact assembly mounted within saidhousing assembly and coupled in electrical communication with saidcapture component cable.
 16. The apparatus of claim 15 in which: saiddelivery cannula, said capture component, said support member, saiddrive assembly, said cable terminator component, said cable stop memberand said electrical contact assembly are combined in operationalassociation with a support housing configured for operative associationwith a housing component of said housing assembly to provide a discreteremovable component of said apparatus.
 17. The apparatus of claim 1 inwhich: said capture component forward portion comprises: a plurality ofdiscrete cage defining leafs, each having a tip portion and a width andthickness between sides which are generally parallel with saidlongitudinal axis, a guidance assembly fixed to said delivery cannula atsaid forward region and configured to effect deployment of said leafsinto tissue at a predetermined angle of attack, and said leaf thicknessis of an extent effecting formation of a generally curvilinear cageperiphery when said capture component forward portion is subsequentlyextended while being drawn in contraction toward said axis.
 18. Theapparatus of claim 17 in which: each said leaf is formed of metal; andeach said leaf includes an electrically insulative coating having athickness in a range of about 0.00025 inch to about 0.005 inch.
 19. Theapparatus of claim 17 in which: each said leaf is formed of metal; andeach said leaf includes an electrically insulative coating having athickness in a range of about 0.0005 inch to about 0.0025 inch.
 20. Theapparatus of claim 17 in which: said leaf width is of an extenteffective to provide extensional cage defining stable movement of saidleafs through said guidance assembly along said plane extending throughsaid longitudinal axis.
 21. The apparatus of claim 17 in which: said tipportions of said leafs incorporate apertures dimensioned to receive saidflexible pursing cable assembly in slideable relationship; said pursingcable assembly is comprised of a number of discrete cables, each passingthrough a predetermined number of said apertures and having a forwardend fixed to the tip portion of a said leaf; and the said number ofdiscrete cables is selected with respect to the number of said leafs toderive the shape of said curvilinear cage periphery.
 22. The apparatusof claim 21 in which each said leaf having a said aperture through whicha said discrete cable initially extends includes a cable guide fixed tosaid leaf and into which said discrete cable extends.
 23. The apparatusof claim 22 in which said cable guide comprises a flexible polymerictube.
 24. The apparatus of claim 22 in which said capture componentcomprises five said leafs and five said discrete cables.
 25. Theapparatus of claim 1 in which said delivery cannula includes anevacuation channel connectable with a vacuum source and extending fromsaid proximal end portion to at least one suction port at said forwardregion, and including an outwardly extending continuous steam migrationblock surrounding said cannula adjacent said port.
 26. Apparatus forretrieving a tissue volume of given peripheral extent, comprising: adelivery cannula having an outer surface surmounting an interior channeland extending from a proximal end portion along a longitudinal axis to aforward region having a distal end positionable in confronting adjacencywith said tissue volume; a capture component positioned within saiddelivery cannula interior channel, having a forward portion extending toa forwardly disposed electrically conducting electrosurgical cuttingleading edge portion and being extendible toward an outer peripheraldimension effective for the circumscriptive engagement of said tissuevolume peripheral extent when moved along said longitudinal axis toegress from said delivery cannula: a housing assembly having forward andrearward portions and coupled in supporting relationship with saiddelivery cannula at said proximal end portion; a drive assemblyincluding a drive component extending from driving engagement with saidcapture component within said delivery cannula interior channel intosaid housing and having a drive member with a driven surface fixed tosaid drive component in driving relationship, said drive member beingmovable along said axis from a start orientation to a capture position;an actuator assembly within said housing including an elongaterotational translation component located in generally parallelrelationship with said drive assembly, fixed for rotation at saidhousing forward portion and extending rearwardly therefrom to aself-aligning coupling assembly having a forward driving connectionportion coupled therewith and an rearward driven connection portion, amotor assembly having a rotational drive output coupled in drivingrelationship with said coupling assembly rearward driven connectionportion, said motor assembly being mounted in self-aligning confinementwithin said housing assembly, having non-rotational freedom of movementextending from said coupling assembly and being actuable to drive saidtranslation component from said coupling assembly; a transfer assemblymounted in driven relationship with said rotational translationcomponent having a home position in association therewith and having anengaging portion engagable in driving relationship with said drivemember driven surface to effect movement of said drive member along saidaxis when said motor assembly is actuated; and a terminal assemblyresponsive to an applied control input for effecting the application ofelectrosurgical cutting current to said capture component leading edgeportion.
 27. The apparatus of claim 26 in which said transfer assemblyengaging portion is configured for freely abutting contact with saiddrive assembly drive member driven surface.
 28. The apparatus of claim26 in which: said transfer assembly is movable by said translationcomponent from a home position toward said housing forward portion whensaid motor assembly is actuated, said movement being carried out untilsaid drive member arrives at a capture completing location along saidlongitudinal axis effecting a forward stall condition of said motorassembly.
 29. The apparatus of claim 28 in which: said motor assembly isresponsive to reverse its rotational drive output in the presence ofsaid forward stall condition to effect the return of said transferassembly to said home position by said translation component.
 30. Theapparatus of claim 29 further comprising a drive stop assemblyengageable with said drive member at a location forwardly beyond saidcapture position to limit said movement along said axis.
 31. Theapparatus of claim 29 in which: said motor assembly is responsive toterminate its rotational drive output in the presence of a reverse stallcondition.
 32. The apparatus of claim 26 in which said coupling assemblyof said actuator assembly comprises: a coupling chamber within saidhousing; a coupler extending through said coupling chamber and connectedbetween said rotational translation component and said motor assemblyrotational drive output; and a fluid seal surmounting said couplerwithin said coupling chamber.
 33. The apparatus of claim 26 in whichsaid coupling assembly comprises a torsionally rigid and axiallyflexible coupler connected between said rotational translation componentand said motor assembly rotational drive output.
 34. The apparatus ofclaim 33 in which said coupler is configured as a bellows.
 35. Theapparatus of claim 33 in which said coupler is a U-joint coupling. 36.The apparatus of claim 26 in which said coupler is an elastomeric tube.37. The apparatus of claim 33 in which said rotational translationcomponent is configured with helical threads and is rotatably coupled instress transfer relationship with said housing forward portion through athrust bearing.
 38. The apparatus of claim 26 in which: said deliverycannula, said capture component, said drive assembly and an electricalcontact assembly component of said terminal assembly coupledelectrically with said capture component leading edge portion arecombined in operational association with a support housing configuredfor operative association with a housing component of said housingassembly to provide a discrete removable component of said apparatus;and said housing incorporates a receiving region extending rearwardlyfrom said housing forward portion and configured for receiving saidsupport housing in an operational association wherein, when said supporthousing is installed at said receiving region, said electrical contactassembly is in electrical communication with said terminal assembly, andsaid transfer assembly is at said home position and oriented forengagement with said drive member driven surface.
 39. The apparatus ofclaim 38 in which: said drive assembly includes an elongate supportmember extending within said delivery cannula interior channel alongsaid longitudinal axis into said support housing; said drive componentand said drive member are mounted for movement along said supportmember; and said drive member driven surface extends outwardly from saidsupport housing and is configured for manual grasping and movementtoward said start orientation from said capture position.
 40. Theapparatus of claim 39 in which said drive assembly includes a latchassembly mounted within said support housing forwardly from said drivemember start orientation to limit rearward movement thereof.
 41. Asystem for carrying out a procedure for retrieving a tissue volume,comprising: a delivery cannula having an outer surface surmounting aninterior channel and extending from a proximal end portion along alongitudinal axis to a forward region having a distal end positionablein confronting adjacency with said tissue volume; a capture componentpositioned within said delivery cannula interior channel at said forwardregion having a containment structure extending to a forwardly disposedpursing cable assembly energizable to define an electrosurgical cuttingleading edge, said containment structure being extensible from saidforward region at an angle of attack with respect to said axis to definean outer periphery having a dimension effective for the circumscriptiveengagement of said tissue volume and subsequently extendable while saidleading edge is drawn in contraction toward said axis by a pursingstress applied to said pursing cable assembly; a housing assemblycoupled in supporting relationship with said delivery cannula at saidproximal end portion; a drive assembly including a drive componentextending from driving engagement with said containment structure withinsaid delivery cannula into said housing and having a drive member with adriven surface fixed to said drive component in driving relationship,said drive member being movable along said axis from a start orientationto a capture position a translation component within said housinglocated in generally parallel relationship with said drive assembly,responsive to a rotational drive input to provide a translation driveoutput; a transfer assembly within said housing, coupled in drivenrelationship with said translation drive output, having a home position,having an engaging portion engagable in driving relationship with saiddrive member driven surface to effect movement of said drive memberalong said axis; a motor within said housing for providing saidrotational drive input to said translation component, having loadcurrent characteristics, responsive to a forward input to provide aforward said rotational drive input and to a reverse input to provide arearward said rotational drive input; an electrosurgical generatorhaving an output connectable with said capture component pursing cableassembly and responsive to an energize input to provide electrosurgicalcutting energy having a voltage level at said output; and a controlassembly connected with said motor and said electrosurgical generator,responsive to a capture input to provide said energize input to saidelectrosurgical generator and effect application of said electrosurgicalcutting energy to said pursing cable assembly and to provide saidforward input to said motor, responsive to terminate said forward inputwhen a said motor load characteristic corresponds with the presence ofsaid drive member at said capture position.
 42. The system of claim 41in which: said control assembly is responsive to provide said reverseinput to said motor when said motor load characteristic corresponds withthe presence of said drive member at said capture position.
 43. Thesystem of claim 42 in which said control assembly is responsive toterminate said reverse input when said motor load characteristiccorresponds with said transfer assembly reaching said home position. 44.The system of claim 43 in which said transfer assembly engaging portionis engageable in freely abuttable driving relationship with said drivemember driven surface and releases from said engagement in the presenceof said reverse input to said motor when said motor load characteristiccorresponds with the presence of said drive member at said captureposition.
 45. The system of claim 41 in which said control assembly isresponsive to a start procedure input occurring prior to said captureinput to provide said reverse input to said motor and subsequently isresponsive to terminate said reverse input when said motor loadcharacteristic corresponds with the presence of said transfer assemblyat said home position.
 46. The system of claim 45 in which said controlassembly is responsive at the said termination of said reverse inputwhen said motor load characteristic corresponds with the presence ofsaid transfer assembly at said home position to provide said forwardinput to said motor for an interval effective to reduce stress at saidmotor and said transition component.
 47. The system of claim 41 furthercomprising: a drive stop assembly engageable with said drive member at alocation forwardly beyond said capture position to terminate saidmovement along said axis; and said control assembly is responsive to aforward stall said motor load characteristic when said drive memberengages said drive stop assembly to terminate said forward input to saidmotor.
 48. The system of claim 41 in which: said transfer assemblyengaging portion is spaced from said drive member driven surface apreliminary drive distance when said drive member is at said startorientation and said transfer assembly is at said home position; andsaid control assembly is responsive to said capture input to provide atest said forward input to said motor for a predetermined test intervaloccurring prior to said provision of said energize input to saidelectrosurgical generator is responsive to halt said procedure when saidmotor load characteristic exceeds a predetermined low load thresholdvalue.
 49. The system of claim 48 in which said control assembly isresponsive to a said load characteristic corresponding with a drivingengagement of said transfer assembly engaging portion with said drivemember driven surface to terminate the test said forward input to saidmotor.
 50. The system of claim 41 in which: said electrosurgicalgenerator is responsive to a boost said energize input to provide saidelectrosurgical cutting energy at an arc initiating boost said voltagelevel effective to initiate an arc when said electrosurgical cuttingleading edge is in contact with tissue; and said control assembly isresponsive to said capture input to provide said energize input to saidelectrosurgical generator as a boost energize input for a boostinterval.
 51. The system of claim 41 comprising: a precursorelectrosurgical electrode assembly having a precursor input, supportedforwardly from said delivery cannula distal end and having a tissueencountering and severing portion generally extending normally to saidlongitudinal axis and energizable with said cutting energy to facilitatethe positioning of said distal end in confronting adjacency with saidtissue volume; said electrosurgical generator is responsive to a boostsaid energize input to provide said electrosurgical cutting energy at anarc initiating boost voltage level effective to initiate an arc whensaid tissue encountering and severing portion is in contact with tissue;and said control assembly is responsive to a position input to providesaid energize input to said electrosurgical generator and effectapplication of said electrosurgical energy to said precursor input atsaid boost voltage level for a boost interval.
 52. The system of claim41 in which: said electrosurgical generator is responsive to a cut saidenergize input to provide said electrosurgical cuffing energy at a cutsaid voltage level and is responsive to a boost said energize input toprovide said electrosurgical cutting energy at a boost said voltagelevel greater than said cut voltage level; and said control assembly isresponsive to said capture input to provide said energize input to saidelectrosurgical generator as a boost energize input for a boost start-upinterval and to provide said energize input as a cut energize input atthe termination of said boost interval.
 53. The system of claim 52comprising: a precursor electrosurgical electrode assembly having aprecursor input, supported forwardly from said delivery cannula distalend and having a tissue encountering and severing portion generallyextending normally to said longitudinal axis and energizable with saidcutting energy to facilitate the positioning of said distal end inconfronting adjacency with said tissue volume; and said control assemblyis responsive to a position input to provide said energize input to saidelectrosurgical generator and effect application of said electrosurgicalcutting energy to said precursor input as a boost energize input for aboost interval and to provide said energize input as a cut energizeinput at the termination of said boost interval.
 54. The system of claim41 including: a precursor electrosurgical electrode assembly having aprecursor input, supported forwardly from said delivery cannula distalend and having a tissue encountering and severing portion extendingnormally to said longitudinal axis and outwardly from said outer surfacea distance selected in correspondence with said capture component outerperiphery and located for circuit completing contacting engagement withsaid capture component pursing cable assembly when said containmentstructure is extended from said forward region of said delivery cannula;and said control assembly is responsive to a position input to providesaid energize input to said electrosurgical generator and to connectsaid electrosurgical cutting energy to said precursor input, isresponsive to the removal of said position input to disconnect saidelectrosurgical cutting energy from said precursor input to enable theapplication of electrosurgical cutting energy thereto from said capturecomponent pursing cable assembly.
 55. The system of claim 41 in whichsaid control assembly includes a manually actuable tissue capture switchand a footswitch actuable between off and on conditions, said controlassembly being responsive to actuation of said tissue capture switch orsaid footswitch to said on condition to derive said capture input. 56.The system of claim 55 in which said control assembly tissue captureswitch is mounted upon said housing.
 57. The system of claim 55 in whichsaid control assembly is responsive to an actuation of said tissuecapture switch or said footswitch to said off condition in the presenceof said capture input to terminate said capture input and enter a pausemode.
 58. The system of claim 57 in which said control assembly includesa pause indicator component energizable to provide a perceptible outputin the presence of said pause mode.
 59. The system of claim 41 in whichsaid control assembly includes a tissue capture switch actuable betweenoff and on conditions, and an arm switch actuable between off and onconditions, said control assembly being responsive to actuation of saidarm switch to said on condition to derive an arm capture mode, and beingresponsive to said actuation of said tissue capture switch to said oncondition to derive said capture input in the presence of said armcapture mode.
 60. The system of claim 59 in which said control assemblyincludes an arm capture output indicator component energizable toprovide a perceptible output in the presence of said arm capture mode.61. The system of claim 59 in which: said capture component containmentstructure leading edge is drawn in said contraction toward said axis bya said pursing stress applied to said pursing cable assembly effectiveto derive a capture complete status terminating said contraction; andsaid control assembly includes a capture complete indicator componentenergizable to provide a perceptible output in the presence of saidcapture complete status.
 62. The system of claim 59 in which saidcontrol assembly is responsive to an actuation of said tissue captureswitch to said off condition to terminate said capture input and enter apause mode.
 63. The system of claim 62 in which said control assembly isresponsive to an actuation of said tissue capture switch to said oncondition when in said pause mode to derive said capture input.
 64. Thesystem of claim 59 in which said tissue capture switch and said armswitch are mounted upon said housing.
 65. The system of claim 59including: a precursor electrosurgical electrode assembly having aprecursor input, supported forwardly from said delivery cannula distalend, having a tissue encountering and severing portion extendingnormally to said longitudinal axis and configured to facilitate thepositioning of said distal end in said confronting adjacency with saidtissue volume; and said control assembly includes a position switchmanually actuable to provide a position input, said control assemblybeing responsive to said position input in the absence of said armcapture mode to provide said energize input to said electrosurgicalgenerator and to connect said electrosurgical cutting energy to saidprecursor input.
 66. The system of claim 59 including: a precursorelectrosurgical electrode assembly having a precursor input, supportedforwardly from said delivery cannula distal end, having a tissueencountering and severing portion extending normally to saidlongitudinal axis and configured to facilitate the positioning of saiddistal end in said confronting adjacency with said tissue volume; andsaid control assembly includes a position switch as a footswitchactuable in the absence of said arm capture mode to provide saidenergize input to said electrosurgical generator and to connect saidelectrosurgical cutting energy to said precursor input.
 67. The systemof claim 65 in which said tissue capture switch, said arm switch andsaid position switch are mounted upon said housing.
 68. The system ofclaim 65 in which said tissue capture switch, said arm switch and saidposition switch are configured as footswitches.
 69. The system of claims67 or 68 in which said position switch is located intermediate saidtissue capture switch and said arm switch.
 70. The system of claim 41 inwhich said control assembly is responsive to provide said forward inputto said motor when said transfer assembly engaging portion is drivablyengaged with said drive member and effecting its said movement alongsaid axis in the presence of a said motor load characteristic exceedinga predetermined motor engaged threshold value.
 71. The system of claim41 in which said control assembly is responsive to halt said procedurewhen said transfer assembly engaging portion is drivably engaged withsaid drive member and effecting its said movement along said axis in theabsence of a said motor load characteristic exceeding a predeterminedmotor engaged threshold value.
 72. The system of claim 41 in which saidcontrol assembly is responsive to provide a said forward input to saidmotor providing said rotational drive input to said translationcomponent effecting said movement of said drive member along said axisby said transfer assembly at a rate of from about one millimeter persecond to ten millimeters persecond.
 73. The system of claim 41 in whichsaid control assembly is responsive to provide a said forward input tosaid motor providing said rotational drive input to said translationcomponent effecting said movement of said drive member along said axisby said transfer assembly at a rate of from about two and one-halfmillimeters per second to four millimeters per second.
 74. The system ofclaim 41 comprising: a vacuum generating assembly having a vacuum portand actuable to generate a vacuum at said vacuum port effective for thecollection of electrosurgically caused smoke and steam; said deliverycannula includes an evacuation channel having an evacuation input atsaid proximal end portion and extending to at least one suction port atsaid forward region; a vacuum conduit coupling said vacuum port withsaid evacuation input in vacuum deriving association; a vacuumresponsive switch responsive to the presence of a vacuum conditiongenerated at said vacuum port for providing a vacuum signal; and saidcontrol assembly is responsive in the presence of said vacuum signal tosaid capture input.
 75. A system for retrieving a tissue volume,comprising: a delivery cannula having an outer surface surmounting aninterior channel and extending from a proximal end portion along alongitudinal axis to a forward region, having a distal end positionablein confronting adjacency with said tissue volume; a capture componentpositioned within said delivery cannula interior channel, having aforward portion extending to a forwardly disposed electricallyconducting electrosurgical cutting leading edge portion extendableoutwardly from said delivery cannula forward portion to establish anouter peripheral dimension selected for the circumscriptive engagementof said tissue volume and subsequently extendable while being drawn incontraction toward said longitudinal axis to a capture orientation; adeployment assembly extending within said interior channel, drivablycoupled with said capture component and controllable to effect saidextension of said capture component and including an input assembly fortransmitting an electrical cutting energy input to said leading edgeportion; an electrosurgical generator connectable with a power input,including: an input treatment network responsive to said power input toderive an interim voltage output of first value; a first inverternetwork responsive to said interim voltage and to a first invertercontrol input to derive a first alternating voltage output of secondvalue less than said first value at a first inverter output; a firstinverter control network coupled with said first inverter network andderiving said first inverter control input; a rectifier networkresponsive to said first alternating voltage output to derive a linkoutput at a d.c. voltage level corresponding with said first alternatingvoltage output second value; a second inverter network having an input,and responsive to said link output to derive a second alternatingvoltage output at an electrosurgical frequency value and with voltageamplitudes established by said link output d.c. voltage level; a secondinverter control network coupled with said second inverter network toeffect derivation of said second alternating voltage outputelectrosurgical frequency; a high voltage transformer having a primaryside responsive to said second alternating voltage output and asecondary side deriving said electrical cutting energy input at anelectrosurgical voltage level and at said electrosurgical frequency; andan output stage coupled with said high voltage transformer secondaryside and connectable in electrical communication with said inputassembly of said deployment assembly.
 76. The system of claim 75 inwhich said first inverter control network derives said first invertercontrol input to effect a resonant transition phase shift control ofsaid first inverter.
 77. The system of claim 75 in which said firstinverter control network comprises: a voltage monitoring circuitresponsive to said electrical cutting energy input to derive a programsignal; and a controller network responsive to said program signal toderive said first inverter control input.
 78. The system of claim 75comprising: a high voltage monitor responsive to said electrical cuttingenergy input to derive a high voltage monitor signal; and said firstinverter control network comprises: a comparator network responsive to apredetermined electrosurgical cutting voltage level and to said highvoltage monitor signal to derive a program signal; and a controllernetwork responsive to said program signal to derive said first invertercontrol input.
 79. The system of claim 78 in which said controllernetwork is configured derive said first inverter control input as aslowly applied said program signal.
 80. The system of claim 79 in whichsaid first inverter control network comprises: a link voltage monitorresponsive to said link output to provide a link voltage controllingfeedback signal; and said controller network is further responsive tosaid link voltage controlling feedback signal to derive said firstinverter control input.
 81. The system of claim 75 comprising: a controlassembly actuable to derive a boost voltage signal for a boost interval;and said first inverter control network is responsive to said boostvoltage signal to derive a said first inverter control input effectingderivation of said first alternating voltage output second value at aboost voltage value, and is responsive thereafter to derive said firstinverter control input effecting derivation of said first alternatingvoltage output second value at a normal cut voltage value less than saidboost voltage value.
 82. The system of claim 81 in which said boostvoltage valve is greater than said normal cut voltage value by a factorwithin a range from about 1.2 to about 1.5.
 83. The system of claim 75including an isolation transformer having a primary side coupled withsaid first alternating output and a secondary side providing said firstalternating voltage output to said rectifier network.
 84. The system ofclaim 75 in which said second inverter network comprises a resonant tankcircuit.
 85. The system of claim 81 in which said boost interval isabout 100 to 1000 milliseconds.
 86. The system of claim 81 in which saidboost interval is about 250 to 750 milliseconds.
 87. The system of claim81 in which said boost voltage value effects derivation of a said selectelectrosurgical cutting voltage level of about 1000 volts peak-to-peakto about 2000 volts peak-to-peak.
 88. The system of claim 81 in which inwhich said boost voltage value effects derivation of a said selectelectrosurgical cutting level of about 1100 volts, peak-to-peak to about1300 volts, peak-to-peak.
 89. The system of claim 87 in which saidnormal cut voltage value effects derivation of said selectelectrosurgical cutting voltage level of about 700 volts, peak-to-peakto about 1200 volts, peak-to-peak.
 90. The system of claim 88 in whichsaid normal cut voltage value effects derivation of said selectelectrosurgical cutting voltage level of about 800 volts, peak-too-peakto about 1000 volts, peak-to-peak.
 91. The system of claim 75 in whichsaid input treatment network comprises: a boost converter networkresponsive to a converter control input to derive said interim voltageof first value; and a converter control network responsive to said powerinput and to said interim voltage first value to derive a said convertercontrol input effective to provide power factor correction.
 92. Thesystem of claim 75 comprising: a relay switch connected between saidrectifier network and said second inverter network input and responsiveto a relay control input to convey or terminate conveyance of said linkoutput to said second inverter network; and a control assemblyresponsive to a fault condition to derive a said relay control inputterminating conveyance of said link output to said second inverternetwork input.
 93. The system of claim 92 in which: said first invertercontrol network comprises a power monitoring circuit responsive to saidelectrical cutting energy input to derive a power signal correspondingwith the level of power exhibited by said electrical cutting energyinput; and said control assembly is responsive to derive a said relaycontrol input terminating said conveyance of said link output when saidpower signal exceeds a power threshold level.
 94. The system of claim 92comprising: a high voltage monitor responsive to said electrical cuttingenergy input to derive a high voltage monitor signal; and said controlassembly is responsive to derive a said relay control input terminatingsaid conveyance of said link output when said high voltage monitorsignal exceeds a high voltage threshold level.
 95. The system of claim92 comprising: a high voltage current monitor responsive to saidelectrical cufting energy input to derive a high voltage current monitorsignal; and said control assembly is responsive to derive a said relaycontrol input terminating said conveyance of said link output when saidhigh voltage current monitor signal exceeds a current threshold level.96. The system of claim 92 comprising: a link voltage monitor responsiveto said rectifier network link output to derive a link monitor signalcorresponding with said link output d.c. voltage level; and said controlassembly is responsive to derive a said relay control input terminatingsaid conveyance of said link output when said link monitor signalcorresponds with a said link output d.c. voltage level which exceeds alink over-voltage threshold level.
 97. The system of claim 96 in whichsaid control assembly is responsive to derive said relay control inputterminating said conveyance of said link output when said link monitorsignal corresponds with a said link output d.c. voltage level which isbelow a predetermined under-voltage threshold level.
 98. Apparatus forretrieving a tissue volume, comprising: a delivery cannula having anouter surface surmounting an interior channel and extending from aproximal end portion along a longitudinal axis to a forward regionhaving a distal end positionable in confronting adjacency with saidtissue volume.; a capture component positioned within said deliverycannula at said forward region, having a forward portion comprising aplurality of leafs having widths and thicknesses effective for lateralstability and flexure, each leaf having a length extending from a baseportion to said forward portion and having a tip portion, each said tipportion having a pursing eyelet, a retainer groove extending along thelength of each said leaf, a cable guide fixed to each said leaf at saidretainer groove, the base portions of said leafs being interconnected todefine a tube structure base supporting forwardly extending discretesaid leafs at said forward portion, a pursing cable assembly comprisedof a plurality of discrete electrically conductive cables each slideablyextending through a said cable guide and an associated said pursingeyelet and from said pursing eyelet extending to and connected to thetip portion of a next adjacent said leaf, a guidance assembly fixed tosaid delivery cannula at said forward region and configured to effectdeployment of said leafs mutually outwardly from said longitudinal axis;a housing assembly coupled in supporting relationship with said deliverycannula at said proximal end portion; a drive assembly including a driverod connected with said capture component tube structure base withinsaid delivery cannula interior channel and extending into said housingassembly, said drive rod being drivably movable along said axis toeffect extension of said leaf forward portions and associated saidcables mutually outwardly from said guidance assembly to establish aperiphery of predetermined effective diametric extent defined by saidtip portions, thereafter said drive assembly controlling movement ofsaid cables while said drive rod is moved along said axis to effect amutually inward flexure of said leaf tip portions to a captureorientation for enveloping said tissue volume; and an actuator andcontrol assembly drivably engagable with said drive assembly to effectmovement of said drive rod and to effect electrosurgical cuttingenergization of said cables.
 99. The apparatus of claim 98 in which eachsaid leaf is coated with a vitreous material.
 100. The apparatus ofclaim 98 in which each said leaf is coated with an electricallyinsulative material.
 101. The apparatus of claim 98 in which each saidleaf is coated with an electrically insulative polymeric material. 102.The apparatus of claim 98E in which each said cable guide is a flexiblemetal tube coated with an electrically insulative material.
 103. Theapparatus of claim 98 in which each said leaf is coated with avapor-phase-polymerized conformal coating.
 104. The apparatus of claim98 in which each said cable guide is fixed to each said leaf with avapor-phase-polymerized conformal coating.
 105. The apparatus of claim98 in which each said cable guide is an electrically insulative guidetube fixed to each said leaf with a vapor-phase-polymerized conformalcoating.
 106. The apparatus of claim 105 in which said conformal coatingis poly-para-xylene.
 107. The apparatus of claim 105 in which saidconformal coating has a thickness of from about 0.0002 inch to about0.003 inch.
 108. The apparatus of claim 105 in which said conformalcoating has a thickness of from about 0.00075 inch to about 0.00125inch.
 109. The apparatus of claim 105 in which each said guide tube isformed of a polyamide.
 110. The apparatus of claim 98 in which each saidleaf tip portion is bent generally normally to the widthwise extent ofthe leaf.
 111. The apparatus of claim 98 in which said leafs are formedof stainless steel having a said thickness of about 0.003 inch.
 112. Theapparatus of claim 98 in which said leafs are formed of stainless steeland have a said width of about 0.080 inch.
 113. The apparatus of claim98 in which each one of said discrete cables is formed of a multi-strandbraided stainless steel.
 114. The apparatus of claim 98 in which eachone of said discrete cables has a diameter within a range from about0.002 inch to about 0.020 inch.
 115. The apparatus of claim 113 in whicheach one of said discrete cables has a diameter of about 0.005 inch.116. The apparatus of claim 98 in which: said capture component tubestructure base exhibits a polygonal cross-section with mutually inwardlyfacing surfaces; and said drive assembly drive rod extends within saidtube structure and is attached thereto.
 117. In a system for retrievinga tissue volume wherein a re-usable component is provided having are-usable housing connected in electrical communication with anelectrosurgical generator and control assembly and having a receivingregion for receiving a replaceable component extending about alongitudinal region axis rearwardly from a forward portion, a motorassembly within said re-usable housing coupled in driving associationwith a translation component, a transfer assembly within said re-usablehousing coupled in driven relationship with said translation componentand having a transfer yoke with oppositely disposed drive surfacesmovable forwardly and rearwardly in parallel with said region axis inadjacency with said receiving region from and to a home position, and aninput terminal assembly within said re-usable housing at a locationadjacent said receiving region connectable in said electricalcommunication with said electrosurgical generator, an improvedreplaceable component, comprising; a support housing dimensioned forremovable operative association with said re-usable housing when at anoperative position within said receiving region, said support housinghaving rearward and forward portions and disposed about saidlongitudinal region axis when positioned within said receiving region; adelivery cannula having an outer surface surmounting an interior channeland extending from a proximal end portion fixed to said support housingforward portion along a longitudinal cannula axis to a forward regionhaving a distal end positionable in confronting adjacency with saidtissue volume; a capture component positioned within said deliverycannula interior channel at said forward region, having a forwardportion extending to a forwardly disposed pursing cable assemblyenergizable to define an electrosurgical cutting leading edge portion,and including at least two tensionable cables extending from saidpursing cable assembly into said inner channel, said leading edge ofsaid expansible forward portion being extendable from said deliverycannula laterally outwardly and forwardly toward an outer peripheraldimension having a predetermined diametric extent effective to provide acircumspective positioning about said tissue volume and subsequentlyextendable while being drawn in contraction toward said cannula axis bystress at said pursing cable assembly to a capture orientationenveloping said tissue volume; a drive assembly including a drive rodconnected in driving relationship with said capture component andextending to driven connection with a drive member within said supporthousing and movable therein from a start position along said cannulaaxis, said drive member having oppositely disposed ears extendingoutwardly from said support housing, each having a driven surfaceabuttably engageable with said transfer yoke drive surfaces when saidsupport housing is at said operative position; an elongate supportmember mounted within said support housing and extending along saidcannula axis to said rearward region and slidably supporting said drivemember; a cable stop member fixed to said support member at a stopposition deriving said capture component forward portion outerperipheral dimension; a cable terminator component mounted for movementupon said support member, coupled with and drivably movable by saidcables from an initial position into engagement with said cable stopmember at said stop position; and an electrical contact assembly mountedupon said housing electrically coupled with said cables and engaged withsaid reusable housing contained input terminal assembly when saidsupport housing is at said operative position.
 118. The system of claim117 in which: said support housing is configured with oppositelydisposed elongate drive slots at said forward portion; and said drivemember oppositely disposed ears slidably extend through said driveslots.
 119. The system of claim 117 in which: said support housing isconfigured with oppositely disposed stabilizer slots at said rearwardportion; and said cable terminator component is configured withoppositely disposed tabs extending within and slidable along saidstabilizer slots.
 120. The system of claim 117 including: a precursorelectrosurgical electrode assembly supported forwardly from saiddelivery cannula distal end and having a tissue encountering andsevering portion generally extending normally to said cannula axis andconfigured to facilitate the said positioning of said distal end in saidconfronting adjacency with said tissue volume; and an electricalconnector coupling said electrode with said electrical contact assembly.121. The system of claim 117 including a latch assembly mounted withinsaid support housing forwardly from said drive member start position tolimit rearward movement thereof.
 122. The system of claim 117 in whichsaid capture component comprises: a plurality of discrete cage definingleafs, each having a tip portion and a width and thickness between sideswhich are generally parallel with said cannula axis; a guidance assemblyfixed to said delivery cannula at said forward region and configured toeffect deployment of said leafs into tissue at a predetermined angle ofattack; and said leaf thickness is of an extent effecting formation of agenerally curvilinear cage periphery when said capture component forwardportion is subsequently extended while being drawn in contraction towardsaid cannula axis.
 123. The apparatus of claim 122 in which: said leafwidth is of an extent effective to provide extensional cage definingstable movement of said leafs through said guidance assembly along saidplane extending through said longitudinal axis.
 124. The apparatus ofclaim 122 in which: said tip portions of said leafs incorporateapertures dimensioned to receive said flexible pursing cable assembly inslideable relationship; said pursing cable assembly is comprised of anumber of discrete cables, each passing through a predetermined numberof said apertures and having a forward end fixed to the tip portion of asaid leaf; and the said number of discrete cables is selected withrespect to the number of said leafs to derive the shape of saidcurvilinear cage periphery.
 125. The apparatus of claim 124 in whicheach said leaf having a said aperture through which a said discretecable initially extends includes a flexible guide tube fixed to saidleaf and into which said discrete cable extends.
 126. The apparatus ofclaim 125 in which said capture component comprises five said leafs andfive said discrete cables.
 127. The method for isolating and retrievinga tissue volume of given peripheral extent within adjacent tissue of apatient comprising the steps of: (a) providing an electrosurgicalgenerator controllable to derive an electrosurgical cutting output at acutting voltage level; (b) providing a tissue retrieval instrumenthaving a delivery cannula with an internal channel and extending from aproximal end portion along a longitudinal axis to a forward regionhaving a tip, said instrument having a capture component positionedwithin said delivery cannula internal channel having a forward portionextending to a forwardly disposed pursing cable assembly energizable todefine an electrosurgical cutting leading edge, said capture componentbeing actuable to cause said leading edge to extend from said deliverycannula laterally outwardly and forwardly toward a maximum peripheralextent selected to correspond with said given peripheral extent andsubsequently extendable while being drawn toward said axis to a captureorientation, a controllable motor assembly, a translation assembly, atransfer assembly and a drive assembly configured for actuating saidcapture component, said instrument further including a precursorelectrode assembly mounted at said delivery cannula tip and energizablefor electrosurgical cutting from said electrosurgical generator; (c)providing a control assembly, electrically coupled with saidelectrosurgical generator and said instrument, having a position switch,an arm switch and a capture switch, each said switch having an oncondition and an off condition; (d) electrosurgically exciting saidprecursor electrode by actuating said position switch to said oncondition causing said control assembly to assume a position mode; (e)positioning said delivery cannula within said adjacent tissue in amanner wherein said tip is in confronting adjacency with said tissuevolume; (f) causing said control assembly to enter an arm capture modeterminating said excitation of said precursor electrode, terminatingsaid position mode and disabling said position switch, by actuating saidarm switch to said on condition; (g) causing said control assembly toenter a capture mode effecting the electrosurgical excitation of saidpursing cable assembly and controlling said motor to commence actuationof said capture component by applying forward drive to said translationassembly and effecting forward movement of said translation assembly inengagement with said drive assembly to actuate said capture component toeffect an isolation and envelopment of said tissue volume, by actuatingsaid capture switch to said on condition; (h) detecting the reaching ofsaid capture orientation by said capture component with said controlassembly to provide a capture complete mode terminating said capturemode, controlling said motor to terminate said actuation of said capturecomponent and terminating said electrosurgical excitation of saidpursing cable assembly; and (i) removing said delivery cannula with thecapture component retained isolated tissue volume from said adjacenttissue.
 128. The method of claim 127 in which: subsequent to said step(f) for causing said control assembly to enter an arm capture mode,carrying out the steps of: (f1) causing said control assembly tore-enter said position mode from said arm capture mode by actuating saidarm switch to said on condition; (f2) then reiterating said step (e);and (f3) then reiterating said step (f) to cause said control assemblyto re-enter said arm capture mode.
 129. The method of claim 127 inwhich: said step (g) for causing said control assembly to enter acapture mode includes the step of: (g1) causing said control assembly toenter into and maintain said capture mode by actuating said captureswitch to said on condition and maintaining said on conditioncontinuously.
 130. The method of claim 129 in which: said step (g) forcausing said control assembly to enter a capture mode includes the stepof: (g2) subsequent to said step (g1) for actuating said capture switchinto said on condition, actuating said capture switch into said offcondition to cause said control assembly to enter a pause modecontrolling said motor to terminate said actuation of said capturecomponent and controlling said electrosurgical generator to effecttermination of electrosurgical excitation of said pursing cableassembly.
 131. The method of claim 130 in which said step (c) providessaid position switch, said arm switch and said capture switch asfootswitches.
 132. The method of claim 130 in which: said step (g) forcausing said control assembly to enter a capture mode includes the stepsof: (g3) subsequent to said step (g2) for causing said control assemblyto enter a pause mode, re-entering said arm capture mode by actuatingsaid arm switch; and (g4) then re-entering said capture mode byactuating said capture switch into said on condition.
 133. The method ofclaim 132 in which said step (g4) is carried out by initially effectingthe electrosurgical excitation of said pursing cable assembly for apredetermined interval and then controlling said motor to recommenceactuation of said capture component in conjunction with continuedelectrosurgical excitation of said pursing cable assembly.
 134. Themethod of claim 132 in which said step (g4) includes the steps of: (g4a) controlling said electrosurgical generator with said control assemblyto provide said electrosurgical cutting output at a boost cuttingvoltage level for a boost interval; and (g4 b) then controlling saidelectrosurgical generator with said control assembly to provide saidelectrosurgical cutting output at a normal cutting voltage level lessthan said boost cutting voltage level.
 135. The method of claim 134 inwhich said step (g4) is carried out by initially effecting the saidelectrosurgical excitation of said pursing cable assembly for said boostinterval and then controlling said motor assembly to re-commenceactuation of said capture component in conjunction with electrosurgicalexcitation of said pursing cable assembly at said normal cutting voltagelevel.
 136. The method of claim 127 in which said step (d) includes thesteps of: (d1) controlling said electrosurgical generator with saidcontrol assembly to provide said electrosurgical cuffing output at aboost cutting voltage level for a boost interval; and (d2) thencontrolling said electrosurgical generator with said control assembly toprovide said electrosurgical cutting output at a normal cutting voltagelevel less than said boost cutting voltage level.
 137. The method ofclaim 136 in which: said step (dl) provides said electrosurgical cuttingoutput at a said boost cutting voltage level which is greater than saidnormal cutting voltage level by a factor within a range of about 1.2 toabout 1.5.
 138. The method of claim 136 in which: said step (d1)provides said electrosurgical cutting output at said boost cuttingvoltage level for a boost interval of between about 100 milliseconds toabout 1000 milliseconds.
 139. The method of claim 136 in which: saidstep (d1) provides said electrosurgical cutting output at said boostcutting voltage level for a boost interval of between about 250milliseconds to about 750 milliseconds.
 140. The method of claim 136 inwhich said step (g) is carried out by controlling said motor to commenceactuation of said capture component following said boost interval. 141.The method of claim 127 in which said step (g) includes the steps of:(g5) controlling said electrosurgical generator with said controlassembly to provide said electrosurgical cutting output at a boostcutting voltage level for a boost interval; and (g6) then controllingsaid electrosurgical generator with said control assembly to providesaid electrosurgical cutting output at a normal cutting voltage levelless than said boost cutting voltage level.
 142. The method of claim 141in which: said step (g6) provides said electrosurgical cutting output ata said boost cutting voltage level which is greater than said normalcutting voltage level by a factor within a range from about 1.2 to 1.5.143. The method of claim 141 in which: said step (g5) provides saidelectrosurgical cutting output at said boost cutting voltage level for aboost interval of between about 100 milliseconds to about 1000milliseconds.
 144. The method of claim 141 in which: said step (g5)provides said electrosurgical cutting output at said boost cuttingvoltage level for a boost interval of between about 250 milliseconds toabout 750 milliseconds.
 145. The method of claim 127 in which said step(g) is carried out by initially effecting the electrosurgical excitationof said pursing cable assembly for a predetermined interval and thencontrolling said motor to commence actuation of said capture componentin conjunction with continued electrosurgical excitation of said pursingcable assembly.
 146. The method of claim 136 in which: said step (d)provides said electrosurgical cutting output at a said boost cuttingvoltage level of from about 1000 volts, peak-to-peak to about 2000volts, peak-to-peak.
 147. The method of claim 136 in which: said step(d) provides said electrosurgical cutting output at a said boost cuttingvoltage level of from about 1100 volts, peak-to-peak to about 1300volts, peak-to-peak.
 148. The method of claim 127 in which said step (e)is carried out by locating said delivery cannula tip a distance, Ls,from the center of said tissue volume in general correspondence with theexpression: L _(s)=0.6 Dc where, Dc, corresponds with said givenperipheral extent.
 149. The method for isolating and retrieving a tissuevolume of given peripheral extent within adjacent tissue of a patient,comprising the steps of: (a) providing an electrosurgical generatorcontrollable to derive an electrosurgical cutting output at a cuttingvoltage level; (b) providing a tissue retrieval instrument having adelivery cannula with an internal channel and extending from a proximalend portion along a cannula axis to a forward region having a tip, saidinstrument having a capture component positioned within said deliverycannula internal channel, said capture component having a forwardportion extending to a forwardly disposed pursing cable assemblyenergizable to define an electrosurgical cutting leading edge, saidcapture component being actuable to cause said leading edge to extendfrom said delivery cannula laterally outwardly and forwardly toward amaximum peripheral extent selected to correspond with said givenperipheral extent and subsequently extendable while being drawn towardsaid cannula axis to a capture orientation, an energization controlledmotor exhibiting a load characteristic, a translation assembly coupledin driven relationship with said motor, a transfer assembly having adrive surface and movable to and from a home position, and a driveassembly coupled in driven relationship with said capture component foreffecting the actuation thereof and having a driven surface abuttablyengagable with said transfer assembly drive surface and when being at aninitial position spaced a test distance from said transfer assemblydrive surface when said transfer assembly is at said home position (c)providing a control assembly, electrically coupled with saidelectrosurgical generator and said instrument, having a fault conditionoutput, having an arm switch, and a capture switch; (d) positioning saiddelivery cannula within said adjacent tissue in a manner wherein saidtip is in confronting adjacency with said tissue volume; (e) actuatingsaid arm switch to cause said control assembly to enter an arm capturemode; (f) actuating said capture switch in the presence of said armcapture mode to cause said control assembly to enter a capture mode andto control said motor to effect test movement of said translationassembly along said test distance for a test interval; (g) monitoringsaid motor load characteristic with said control assembly during saidtest interval, deriving a said fault condition and terminating saidcapture mode when said load characteristic exceeds a test thresholdlevel; (h) terminating said test movement following said test intervalin the continued presence of said capture mode; (i) then controllingsaid electrosurgical generator with said control assembly to effect theelectrosurgical excitation of said pursing cable assembly in thepresence of said capture mode for an initial interval; controlling saidmotor with said control assembly while continuing said electrosurgicalexcitation of said pursing cable assembly in the presence of saidcapture mode to effect actuation of said capture component by a driveengagement of said transfer assembly drive surface with said driveassembly driven surface to effect isolating envelopment of said tissuevolume; (k) detecting the presence of said capture component captureorientation with said control assembly to enter a capture complete modewherein said electrosurgical generator is controlled to terminate saidelectrosurgical excitation of said pursing cable assembly; and (l)removing said delivery cannula, with the capture component envelopedisolated tissue volume, from said adjacent tissue.
 150. The method ofclaim 149 in which: said step (i) for effecting the electrosurgicalexcitation of said pursing cable assembly for said initial intervalprovides a said cutting voltage level by said electrosurgical generatorat a boost voltage level; and said step (l) for effecting the continuingelectrosurgical excitation of said pursing cable assembly, provides asaid cutting voltage level by said electrosurgical generator at a normalcut voltage level less than said boost voltage level.
 151. The method ofclaim 150 in which said step (i) effects provision of said cuttingvoltage level at a said boost voltage level from about 1000 volts,peak-to-peak to about 2000 volts, peak-to-peak.
 152. The method of claim150 in which said step (i) effects provision of said cutting voltagelevel at a said boost voltage level from about 1100 volts, peak-to-peakto about 1300 volts, peak-to-peak.
 153. The method of claim 149 in whichsaid step (j) for controlling said motor in the presence of said capturemode includes the step: (j1) monitoring said motor load characteristicwith said control assembly during said drive engagement of said transferassembly drive surface with said drive assembly driven surface, andderiving a said fault condition and terminating said capture mode whensaid load characteristic falls below a motor engaged threshold level.154. The method of claim 149 in which said step (k) carries out saiddetecting of said capture orientation by a determination of the presenceof a said load characteristic representing a forward stall of saidmotor.
 155. The method of claim 149 in which said step (k) for detectingthe presence of said capture component capture orientation includes thestep of: (k1) reversing said motor with said control assembly inresponse to said detection to effect movement of said transfer assemblytoward said home position and out of said drive engagement with saiddrive assembly driven surface.
 156. The method of claim 155 in whichsaid step (k) for detecting the presence of said capture componentcapture orientation includes the step of: (k2) detecting the acquiringof said home position by said transfer assembly with said controlassembly and effecting termination of energization of said motor inresponse to said detection of said acquisition.
 157. The method of claim156 in which said step (k2) carries out said detecting of said acquiringof said home position by the determination of the presence of a saidload characteristic representing a reverse stall of said motor.
 158. Themethod of claim 149 in which: said step (c) provides said controlassembly with a start switch; and including the steps of: (m) actuatingsaid start switch prior to said step (e) to carry out reverseenergization control of said motor to effect any available movement ofsaid transfer assembly toward said home position; and (n) then detectingthe presence of said transfer assembly at said home position with saidcontrol assembly and effecting termination of energization of saidmotor.
 159. The method of claim 149 in which: said step (j) foreffecting actuation of said capture component includes the step of: (j1)prior to said step (k) detecting the presence of said capture componentcapture orientation, actuating said capture switch into an off conditionto cause said control assembly to enter a pause mode wherein said motoris controlled to terminate said actuation of said capture component andsaid electrosurgical generator is controlled to effect termination ofelectrosurgical excitation of said pursing cable assembly.
 160. Themethod of claim 159 in which said step (j) for effecting actuation ofsaid capture component includes the step of: (j2) re-entering saidcapture mode by actuating said capture switch into an on condition. 161.The method of claim 160 in which said step (j2) includes the steps of:(j2 a) controlling said electrosurgical generator with said controlassembly to provide said electrosurgical cutting output at a boostcutting level for a boost interval; and (j2 b) then controlling saidelectrosurgical generator with said control assembly to provide saidelectrosurgical cutting output at a normal cutting voltage level lessthan said boost cutting level.
 162. The method of claim 161 in whichsaid step (j2) is carried out by initially effecting the saidelectrosurgical excitation of said pursing cable assembly for said boostinterval and then controlling said motor to recommence actuation of saidcapture component in conjunction with electrosurgical excitation of saidpursing cable assembly at said normal cutting voltage level.
 163. Themethod of claim 155 including the step of: (o) subsequent to said step(k1) for effecting movement of said transfer assembly toward said homeposition, opening said capture component leading edge to access saidisolated and enveloped tissue volume by manually moving said driveassembly toward said initial position.
 164. The method of claim 163 inwhich said step (b) provides a disposable component of said tissueretrieval instrument as comprising said delivery cannula, said capturecomponent and said drive assembly.
 165. The method of claim 149 in whichsaid step (j) controls said motor to effect forward movement of saidtransfer assembly at a rate of from about one millimeter per second toabout ten millimeters per second.
 166. The method of claim 149 in whichsaid step (j) controls said motor to effect forward movement of saidtransfer assembly at a rate of from about two and one-half millimetersper second to about four millimeters per second.
 167. Apparatus forretrieving a tissue volume comprising: a delivery cannula having anouter surface surmounting an interior channel and extending from aproximal end portion along a longitudinal axis to a forward regionhaving a distal end positionable in confronting adjacency with saidtissue volume; a capture component positioned within said deliverycannula interior channel, having a forward portion extending to aforwardly disposed electrically conducting electrosurgical cuttingleading edge portion and being extendable toward an outer peripheraldimension effective for the circumscriptive engagement of said tissuevolume and contractible thereafter toward said axis to envelope saidtissue volume when moved along said longitudinal axis to egress fromsaid delivery cannula; a hand grippable housing having left and rightside portions extending outwardly from a medial plane with a housingforward portion coupled in supporting relationship with said deliverycannula at said proximal end portion; a deployment assembly extendingwithin said interior channel from said housing, drivably coupled withsaid capture component and energizable to effect said movement of saidcapture component along said longitudinal axis; a first switchpositioned adjacent said medial plane at said housing forward portionand manually actuable to energize said deployment assembly; a right gripconnector fixed to said housing right side portion adjacent said forwardportion and said first switch; a left grip connector fixed to saidhousing left side portion adjacent said forward portion and said firstswitch; and a manually graspable stabilizer grip removably connectablewith said right grip connector or said left grip connector.
 168. Theapparatus of claim 167 in which: said right grip connector and said leftgrip connector extend in generally parallel relationship with saidlongitudinal axis; and said stabilizer grip is adjustably connectablewith said right grip connector and said left grip connector in parallelwith said axis to adjust the distance from said grip to said firstswitch.
 169. The apparatus of claim 167 in which said grip is configuredas an annulus.
 170. The apparatus of claim 167 in which: said right gripconnector and said left grip connector are each configured as anelongate platform supported from a pier component fixed to said housingand spacing said platform outwardly therefrom; and said grip isconfigured having an elongate slot configured to slidably receive saidplatform.